***Useful Information for Apprentices***

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“ General Health and Safety at Work “

Question 1.1
What do the letters CDM stand for ?
A: Control of Demolition and Management Regulations
B: Control of Dangerous Materials Regulations
C: Construction (Demolition Management) Regulations
D: Construction (Design and Management Regulations ) Answer: D )
Question 1.2
Identify one method of enforcing regulations that are
available to the Health and Safety Executive:
A: Health Notice
B: Improvement Notice
C: Obstruction Notice
D: Increasing insurance premiums
Answer: B Improvement notices require action to achieve standards which meet health and safety law :
Question 1.3
What happens if a Prohibition Notice is issued by an
Inspector of the local authority or the HSE ?
A: The work in hand can be completed, but no new work started
B: The work can continue if adequate safety precautions are put in place
C: The work that is subject to the notice must cease
D: The work can continue, provided a risk assessment is carried out,
Answer: C The work covered by a prohibition notice must cease until the identified danger is removed.
Question 1.4
Health and Safety Executive Inspector can ?
A: Only visit if they have made an appointment
B: Visit at any time
C: Only visit if accompanied by the principal contractor
D: Only visit to interview the site manager
Answer: B Inspectors have a range of powers, including the right to visit premises at any time.
Question 1.5
A Prohibition Notice means:
A: When you finish the work you must not start again
B: The work must stop immediately
C: Work is to stop for that day only
D: Work may continue until the end of the day
Answer: B The work activity covered by the prohibition notice must cease, until the identified danger is removed ,
Question 1.6
In what circumstances can an HSE Improvement Notice be issued ?
A: If there is a breach of legal requirements
B: By warrant through the police
C: Only between Monday and Friday on site
Answer: A Improvement notices require action to achieve standards which meet health and safety law .
Question 1.7
What is an “Improvement Notice”?
A: A notice issued by the site principal contractor to tidy up the site
B: A notice from the client to the principal contractor to speed up the work
C: A notice issued by a Building Control Officer to deepen foundations
D: A notice issued by an HSE/local authority Inspector to enforce compliance with health
Answer: D Improvement notices require action to achieve standards which meet health and safety law .
Question 1.8
If a Health and Safety Executive Inspector issues a“ Prohibition Notice”, this means that:
A: the Site Manager can choose whether or not to ignore the notice
B: specific work activities, highlighted on the notice, must stop
C: the HSE must supervise the work covered by the notice
D: the HSE must supervise all work from then on
Answer: B Prohibition notices are intended to Stop activities which can cause serious injury.
Question 1.9
Which one of the following items of information will you find on the Approved Health and Safety Law poster?
A: Details of emergency escape routes
B: The location of the local HSE office
C: The location of all fire extinguishers
D: The identity of the first aiders
Answer: B The poster also lists the persons with health and safety responsibilities, but not first aiders.
Question 1.10
Who is responsible for signing a Company Safety Policy ?
A: Site Manager
B: Company Safety Officer
C: Company Secretary
D: Managing Director
Answer: D The Health and Safety at Work Act requires the most senior member of management to sign the health and safety policy
statement.

Question 1.11
Which one of the following must be in a company’s written Health and Safety Policy:
A: Aims and objectives of the company
B: Organisation and arrangements in force for carrying out the health and safety policy
C: Name of the Health and Safety Adviser
D: Company Director’s home address
Answer: B This requirement appears in the Health and Safety at Work Act.
Question 1.12
Employers have to produce a written Health and Safety Policy statement when:
A: A contract commences
B: They employ five people or more
C: The safety representative requests it
D: The HSE notifies them
Answer: B This is a specific requirement of the Health and Safety at Work Act.
Question 1.13
Companies employing five or more people must have a written Health and Safety Policy because:
A: The principal contractor gives them work on site
B: The HSAWA 1974 requires it
C: The Social Security Act requires it
D: The trade unions require it
Answer: B
Question 1.14
What do the letters HSC stand for ?
A: Health and Safety Contract
B: Health and Safety Consultant
C: Health and Safety Conditions
D: Health and Safety Commission Answer: D
Question 1.15
Which ONE of the following statements is correct ? The Health and Safety Executive is:
A: a prosecuting authority
B: an enforcing authority
C: a statutory provisions authority
Answer: B The Health and Safety Executive enforces health and safety legislation.
Question 1.16
The Health and Safety at Work Act requires employers to provide what for their employees?
A: Adequate rest periods
B: Payment for work done
C: A safe place of work
D: Suitable transport to work
Answer: C This is a specific requirement of Section 2 of the Health and Safety at Work Act.
Question 1.17
The Health and Safety at Work Act 1974 and any regulations made under the Act are:
A: Not compulsory, but should be complied with if convenient
B: Advisory to companies and individuals
C: Practical advice for the employer to follow
D: Legally binding Answer: D
Question 1.18
Under the Health and Safety at Work Act 1974, which of the following have a duty to work safely?
A: Employees only
B: The general public
C: Employers only
D: All people at work
Answer: D Employers, employees and the self-employed all have a duty to work safely under the Act.
Question 1.19
What is the MAXIMUM penalty that a Higher Court, can currently impose for a breach of the Health and Safety at Work Act?
A: £20,000 fine and two years imprisonment
B: £15,000 fine and three years imprisonment
C: £1,000 fine and six months imprisonment
D: Unlimited fine and two years imprisonment
Answer: D A Lower Court can impose a fine of up to £20,000 and/or up to six months imprisonment for certain offences. The potential fine in a Higher Court, however, is unlimited and the term of imprisonment can be up to 2 years.
Question 1.20
What do the letters ACoP stand for ?
A: Accepted Code of Provisions
B: Approved Condition of Practice
C: Approved Code of Practice
D: Accepted Code of Practice
Answer: C An ACOP is a code of practice approved by the Health and Safety Commission.

Question 1.21
Where should you look for Official advice on health and safety matters?
A: A set of health and safety guidelines provided by suppliers
B: The health and safety rules as laid down by the employer
C: Guidance issued by the Health and Safety Executive
D: A professionally approved guide book on regulations
Answer: C The HSE is the UK enforcing body and its guidance can be regarded as ‘official’
Question 1.22
Regulations that govern health and safety on construction sites:
A: apply only to inexperienced workers
B: do not apply during ’out of hours’ working
C: apply only to large companies
D: are mandatory ( that is, compulsory )
Answer: D The requirements of health and safety law are mandatory, and failure to follow them can lead to prosecutions.
Question 1.23
Which of the following statements is correct ?
A: The duty for health and safety falls only on the employer
B: All employees must take reasonable care, not only to protect themselves but also their colleagues
C: Employees have no responsibility for Health and Safety on site
D: Only the client is responsible for safety on site
Answer: B The responsibility for management of Health and Safety Act at Work rests with the employer
Question 1.25
Which of the following is correct for risk assessment?
A: It is a good idea but not essential
B: Only required to be done for hazardous work
C: Must always be done
D: Only required on major jobs
Answer: C There is a legal requirement for all work to be suitably risk assessed.
Question 1.26
In the context of a risk assessment, what do you understand by the term risk?
A: An unsafe act or condition
B: Something with the potential to cause injury
C: Any work activity that can be described as dangerous
D: The likelihood that harm from a particular hazard will occur
Answer: D Hazard and risk are not the same. Risk reflects the chance of being harmed by a hazard
Question 1.27
Who would you expect to carry out a risk assessment on your working site?
A: The site planning supervisor
B: A visiting HSE Inspector
C: The construction project designer
D: A competent person
Answer: D A risk assessment must be conducted by a 'competent person’.
Question 1.28
What is a HAZARD ?
A: Where an accident is likely to happen
B: An accident waiting to happen
C: Something with the potential to cause harm
D: The likelihood of something going wrong
Answer: C Examples of hazards include: a drum of acid, breeze blocks on an elevated plank; cables running across a floor.
Question 1.29
What must be done before any work begins ?
A: Emergency plan
B: Assessment of risk
C: Soil assessment
D: Geological survey
Answer: B This is a legal requirement of the Management of Health and Safety at Work Regulations.
Question 1.30
Complete the following sentence: A risk assessment
A: is a piece of paper required by law
B: prevents accidents
C: is a means of analysing what might go wrong
D: isn’t particularly useful
Answer: C Risk assessment involves a careful review of what can cause harm and the practical measures to be taken to reduce the risk of harm.

 

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201-2

• Which of the following would not involve electrotechnical activities ( Automotive wiring companies )
* They are specifically left out of the regs :
• Reference to maintained and non-maintained systems are made ( Emergency lighting installations )
* Some come on normally . others in mains failure .
• What system can control heating and ventilation a construction via a series of sensors . ( Building management system )
* Looks after the whole ………
• A tender to apply to undertake work is normally completed by the ( Estimator )
• A component installed to detect increases in temperature is known as a ( Heat detector )
* Remember there are 2 distinct types .
• Category 6E cabling used in transmission of ( Data )
* Transmits signals .
• A standard ring final socket outlet system is known as a ( Power installation )
* Transmits electricity for general use .
• The jointing of high voltage cables is usually used in ( Distribution networks )
* Moving electricity from one building to another .
• High voltage cable jointing is usually carried out by ( Regional electricity companies )
* Supply companies .
• The industry body that represents employers in electrical contracting is the ( ECA )
* Electrical contracting ……….
• A foreman ( Runs the day to day operations on a construction site )
* Should be making sure you do your job correctly .
• Fibre optic cabling is used in transmission of ( Data )
* Transmits signals via light .
• A system installed to detect the presence of unwanted personnel is known as a ( Security installation )
* Sometimes called burglar alarms .
• The industry body that represents and negotiates on behalf of employees in the electrical contracting industry is the ( JIB )
* Sort out your wages rates .
• A series of pumps and machinery are to be linked together to perform various duties towards the same outcome . this would be known as a ( Control system )
* Everything is ---------- by a single system .
• An estimator is responsible for ( Pricing a potential installation )
* Estimating how much .
• A large industrial panel feeding a large factory has several components installed to monitor voltage . current & power consumption . this is known as . ( Instrumentation )
* Items used to measure thing are called ………..
• A system installed to detect flames or smoke is known as a ( Fire alarm installation )
* easy one here .
• A contracts manager ( Oversees an installation build from start to finish )
* Quite high up in the chain .
• A high voltage supply is normally installed by ( The regional supply authority . )
* Transmission * distribution .

 

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Inspection & Testing – 6

• A polarity test is conducted to verify that ( Every fuse and single pole device is connected in the line conductor only )
* Things work and are protected
• When installing 3-Phase equipment . what additional test should be carried out ( Phase sequence test )
* Maybe the motor spins the wrong way .
• A legible chart . diagram or table relating to the installation should provide information relating to ( The identification of circuit protection )
* Can easily locate the …… in event of fault . maintenance etc .
• An earth fault loop impedance test performed on a ring final circuit will record ( The résistance of the line conductor . protective conductor & external loop impedance )
* Kit . bang . Kaboodle .
• The minimum value of insulation résistance test performed on a PELV installation is ( 0.5MΩ )
* Look up part 6 . SELV –PELV : 250V d.c. ≥ 0.5MΩ . Table 61 .
• An electrical installation certificate must indicate responsibility for the installations ( Design . construction . inspection & testing )
* Start . middle & end perhaps .
• A polarity test should be carried out ( Before the installation is energised )
* Pre or post is the question . or maybe dead or live ?
• The minimum value of insulation résistance test performed on 230V a.c. installation is ( part 6 )
* Look up part 6 . Table 61 . 500V d.c. ≥ 0.1MΩ .
• A minor works certificate should be issued where ( An alteration not requiring an additional circuit needed . )
* Small works .
• An insulation résistance test performed on a PELV installation should be capable of producing a test voltage ( 250V d.c. )
* Part 6 .
• An electrical installation certificate should be signed by ( A competent person )
* Know what you’re doing do we Sis .
• An insulation résistance test is conducted to verify that ( There is no breakdown of the conductor insulation )
* Pretty obvious .
• Before conducting an insulation résistance test you should ( Ensure that all voltage sensitive devices are taken are disconnected )
* Think about the voltage you are putting through .
• A periodic inspection report would be carried out on ( An existing property ) this Q) would be asked by -&-s 2392-10 .
* Over a period of time .
• Four of the tests on a completed installation required by BS-7671 are ( 2 . 3 . 1 . 4 )
1) Insulation résistance .
2) Continuity of protective conductors’ .
3) Continuity of ring final circuits .
4) Polarity .
Which of the following shows the correct sequence of these tests .
* Think about the sequence and what needs to come first .
• An insulation résistance test performed on a 50V a.c. SELV installation should be capable of ( 250Vd.c. )
* Look up part 6 .
• The frequency of a periodic inspection report on an older installation depends upon ( The type . use & operation of the installation )
* A rarely used building or a frequently used.
• The minimum value of insulation résistance test performed on a SELV installation is ( 0.5MΩ )
* Look up part 6 .
• Which one of the following items is included in the checklist during the initial verification of an ( Presence of diagrams & instructions )
* Something to help find your way around .
• Before conducting an insulation résistance test you should ( Ensure that all lamps are removed )
* What might confuse the readings .
• No alteration . temporary or permanent . shall be made to an existing installation unless the ( The existing equipment is adequate for an additional load )
• A test of continuity at each socket outlet of a ring final circuit is carried out to ensure that ( That the Ring is not Interconnected )
* What are the associated dangers .

 

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Unit 2 :
Inspection & Testing & Commissioning .

1) List three widely used types of : ( it’s the Meaning of the Word -&-s always get’s you On )
a) Wiring system .
b) Wring enclosure .

Solution :- ( any 3 )
a) Micc cable .
PVC/SWA cable .
XLPE/SWA cable .
PVC twin & earth cable .
Fire retardant cable .

b) PVC trunking . ( any 3 )
Steel trunking .
PVC conduit .
Steel conduit .
Ducting .

2) When making an Area Safe to Work in :
a) List three Procedures to be taken before commencing work .
b) Describe the permit to work procedure .

Solution :-
a) Use barriers & tapes to cordon off an area .
Place warning signs in appropriate positions .
Isolate equipment from the supply .

b) The permit to work is a formal procedure in the form of written authorisation used to control work in potentially hazardous areas .

3) When carrying out large contracts .
a) List three parties likely to be concerned .
b) State the purpose of a site record .

Solution :-
a) Client .
Contractor .
Supplier .
Consultant .
Sub-contractor . ( any 3 )

b) Provides a continuous . updated record of all activities on site .

4) Describe the use of the following in monitoring the progress of a contract .
a) a Bar chart .
b) a Site diary .
c) Variation orders .

Solution :-
a) To display progress of different parts of a contract graphically .
b) A daily record of events on site .
c) Variation orders are requests for extra work or change to a contract and must be given in writing . the issue of variation orders may affect the main contract progress .

5) With reference to the application and use of residual current devices ( RCD )
a) list three situations where RCD protection is required .
b) State the primary function of an RCD .
c) Describe the term nuisance tripping . **

Solution :-
a) For sockets installed on TT earthing systems . For sockets outlets likely to supply portable equipment used out doors .
where satisfactory values of ( Zs ) cannot be achieved .
b) To limit the severity of electric shock .
c) When tripping occurs due to small leakage currents that do not constitute a real fault . **

 

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Learning Curve Only

Q ) Which is the preferred method of Protection on the D.C. side of a Photovoltaic Power Supply . ?????? ( PV ) 17th Ed .

1) Class 11 or Equivalent Insulation. ( Take your best Shot )
2) Placing Out of Reach .
3) Non-conducting location .
4) Earth free local Equipotential Bonding .

( p/200 – 712.412. )
17th Ed . Protection by the Use of Class 11 or Equivalent Insulation shall preferably be Adopted on the ( D.C.) Side .
PS. This is the Only Book that gives you the Answer’s to your Qs .

This is Just to make you aware of the Q/As that -&-s will as you one day . Amber. ( what is a Motor/Caravan – Touring/Caravan ) it’s the Wording .
p/209 - PS . Electrical Installations in Caravans & Motor Caravans .

Q) The Maximum Interval between Periodic Inspection of a Touring Caravan is ??????
At this time your Scratching your Head . !! ( Fig . 721 – p/211 – Bottom of / Periodic Inspection
Preferably not less than Once Every Three Years . & Annually if the Caravan is Used Frequently ………… etc .

 

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Q ) Regional Electricity Companies are Reluctant to Provide which of the Following to Construction Sites .??

a ) PME Supply . 704.411.3.1.
p/181 : A TN-C-S system shall Not be Used for the Supply to Construction Sites . Except for the Supply to a Fixed Building of the Construction Sites .
( PME : Protective Multiple Earthing )

1) The ( ESQCR ) Prohibit the use of a TN-C-S system for the Supply to a Caravan or Similar Construction .
2) Not Allowed in Certain Location’s i.e. Petrol Station’s .

b) TT Earthing System .
c) Single Phase Supply .
d) Three Phase Supply .

( PME ) Important to Ensure that the Neutral is Kept at Earth Potential by Earthing it at Many Points Along it’s Length / Hence “ Multiple Earthing “

An RCD that is Installed for Protection Against the Risk of Fire must be ?? -&-s
p/113 – 532.1 .
* The RCD shall be Installed at the Origin of the Circuit to be Protected .
Origin of an Installation . p/27
* The Position at which Electrical Energy is Delivered to an Electrical Installation .

 

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During a Test on an Installation . the Following Readings were Obtained : -&-s
( 20MΩ . 8kA . 22mS )
List the Instruments which gave these Readings . ??

i) Insulation Résistance 20MΩ .
ii) Prospective Short Circuit Current Tester . 8kA ( PSSC )
iii) RCD Tester . 22mS

One would use a Multimeter . 17th Edition . Nowadys

 

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Learning Curve :-

Q) The Test for the Continuity of CPC in a Radial Circuit feeding One Socket Outlet uses a Temporary Link and a Milli-Ohm meter .State !!
i) Where the Temporary Link is Connected .
ii) Where the Milli-Ohmmeter is Connected .
iii) What the Meter Readings Represents .

1) Between ( L ) & ( E ) at the Consumer Unit .
2) Between ( L ) & ( E ) at the Socket Outlet .
3) This Value is ( R1 + R2 ) for the Circuit..

Q) The Following Readings were Obtained during the Initial Tests on a Healthy Ring Final Circuit .
L1 – L2 / 0.8Ω : N1 – N2 /0.8Ω : CPC 1 – CPC -2 / 0.8Ω

a) What Readings would you Expect :-
i) Between L & N Conductors at each Socket Outlet ?
ii) Between L & CPC at each Socket Outlet ?
iii) What the L to CPC Reading Represents ?

● 0.4Ω
● 0.4Ω
● ( R1 + R2 ) for the Ring

 

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The Relationship between the Primary & Secondary Voltages
( and the Number of Turns in the Coil )

Primary ( Input ) Voltage = Number of Turns Primary Coils . ( 230V ~ 2000 Turns )
Secondary ( Output ) Voltage = Number of Turns Secondary Coils . ( 100 Turns ~ Output Voltage )
So Output Voltage = Input Voltage x Number of Turns in Secondary in Secondary Coil :-
Number of Turns in Primary Coil .

Vs = 230V x 100T ÷ 2000T = 11.5V

In Symbols : Vp/Vs = Np/Ns & Vs = Vp x Ns /Np .

Learning Curve :
* Power Station Alternators Generate A.C. at a Voltage of 25kV.
Can Produce a Current of Up to 20kA .

The Power Generated by an Alternator can be Calculated From :-
P = I x V . ( 20000A x 25000V = 500000000W ) = 500MW

* if an Alternator has an Output of 500MW at 25kV . & the Voltage is Stepped up to 400kV . the Current will Be :-
I = P/V ( = 500000000W ÷ 400000V = 1250A = 1.25kA )

 

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Alternating Current :

Alternating Current ( a.c. ) is a flow of electrons . which rises to a maximum value in one direction and then falls back to Zero before repeating the process in the opposite direction . in other words . the electrons within the conductor do not drift : flow : in one direction . but actually move backwards & forwards

The journey taken . i.e. starting at Zero . flowing in both directions and then returning to Zero . is called a Cycle . the number of Cycles that occur every second is said to be the Frequency and this is measured in Hertz ( Hz )

* Impedance : Total Opposition to Flow of a.c. in a Circuit . Combining “ Résistance . Inductance “ and “ Capacitance “ Measured in Ohms ( Ω ) Symbol ( Z )
* Inductance : Opposition created by a Changing “ Current “ in a Magnetic Field which induces a “ Voltage “ to Oppose Change in Current . either within a Circuit ( Self- Inductance ) or a Neighbouring Circuit in the same Magnetic Field ( Mutual Inductance ) Measured in Henrys ( H ) symbol L
* Inductive Circuit or Load : Containing Components with Windings . e.g. Motor . Generator or Transformer . which have Inductance .
* Inductive Reactance : Opposition to Flow of a.c. Produced by an Inductor . Measured in Ohms ( Ω ) Symbol XL
* Inductor : Component Introduced into a Circuit to Provide Required amount of Inductance .
* Hypotenuse : Side un a Right-Angle Triangle Opposite to the Right Angle ( Also . Sine . Cosine . Pythagoras “ Theorem )
* True or Active Power : Power Consumed by a Resistor , Dissipated as Heat and Not Returned to the Source ( also . Apparent Power . Reactive Power )

* Phase Voltage : “ Voltage “ Measured across a Single Component in a Three Phase Source or Load .
* Line Voltage : “ Potential Difference “ between any Two-Phase Conductor’s between Source and Load in a Three-Phase Electrical Circuit .

 

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The AM 2 or Achievement Measurement 2 is a Completely External & Independent Assessment of Abilities to Complete an Apprenticeship .

Special Installation or Locations : 17th Editon .

• The maximum length of an extension cord used on a caravan site to connect to socket outlets should be ( 25m ) Fig 708 – p/192 NOTE:
( The Wording “ connect to socket outlets . 721.55.2.6. (ii) p190 / Caravan site wiring Only )
* Part 7 .
• Zone 1 in the bathroom is the ( Area directly above the bath or shower up to 2.25m above finished floor level ) 701.32.3 (i)
* Not quite the extreme end .
• External influences when designing an installation for a marina would include ( Contact of the body with earth potential )
( External influences : 709.512.2.)
i) Presences of water .
ii) Reduction in body résistance . •
iii) Contact of the body with earth potential •
* if the mass of earth is considered ( 0V ) then the sea must also .

• Photovoltaic equipment should always ( Be considered to be energised on the d.c. side ) Section 712 .
* Let there be light …. All the time .
• In agricultural situations . self supported suspension cables should be ( At a height of at least 6m ) 705.522 . (iii)
* Part 7 .
• What is the minimum protection afforded electrical equipment if installed on a Jetty in a marina ( IPX4 ) 709.512.2.1.1. Minimum !! IPX4/IPX5/IPX6.
Water Splashes ( AD4 ) [ Watch the wording !! JettyWharf , Pier . Pontoon . ( the most use IP Rating is IPX4/IPX2 .17th Edition )
* Part 7 .
• Underground distribution cables installed/buried in caravan parks that run under pitches or where pegs may be placed should be installed at a minimum depth of ( At a depth of 0.6m with Additional Mechanical Protection ) 708.521.1.1.
* Part7 .
• Amusement parks & fairground premises should use RCDs to protect all the following except ( SELV circuit . Hint 740.415.1. Additional Protection RCDs )
* Some things just don’t have an earth you know

(T) Inspection & Testing : 740.6. ( Learning Curve )
The Electrical Installation between its Origin & any Electrical Equipment shall be Inspected & Tested after each Assembly on Site .
Note : Internal electrical wiring of roller coasters . electric dodgems & similar equipment are not considered as part of the Verification .
Note : In special cases the number of the Tests may be Modified according to the Type of Temporary electrical installation .

Useful Junk : Amusement Parks & Fairground Premises
The Electricity at Work Regulations 1989 : Design Erection & Verification Electrical Installation in Fairgrounds . YES.

• The specified IP rating for areas with Zone 2 within a bathroom is ( IPX4 . 701.512.2.) In Zone 1 & Zone 2 : IPX4 )
* Not as extreme as Zone 1 or the same .
• A mobile unit should have a connection between the ( Vehicle Chassis & main protective bonding terminal ) 717.411.3.1.2.
* General mass of vehicle .
• Heating units designed to be use underfloor should have a minimum IP rating of ( IPX7 ) 753.512.2.5.
* Specially waterproof .
• Ceiling heating systems temperature shall not exceed ( 80°C )
* Specific section of the Regulations .

( 753.423 Protection against Burns )
In floor areas where contact with Skin or Footwear is possible , [Restricted] the surface temperature of the floor shall be limited ( for Example 35°C )
PS. This is Important – for [Part–P] etc.
753.424.1.1. To avoid the overheating of floor or Ceiling heating systems in buildings . one or more of the following measures shall be applied within the Zone where heating units installed to limit the Temperature to a Maximum of ( 80°C )

• In agricultural premises . final circuits Not Exceeding 32A should be protected by ( 705.411.1. (i) – 30mA – 40mS )
* The usual .
( Watch the Wording on this : (i) Not Exceeding (ii) More Than ) trip up One -&-s
• Electrical equipment installed in Zone O in a swimming Pools should be rated at ( External Influences /Electrical Equipment : IPX8 ) 702.512.2.
* Extreme . ( The Wording - Swimming Baths / Swimming Pools )
• A socket outlet or plug on a mobile vehicle installation should ( 717.55.1. Plugs& Connectors . BS-EN 60309-2 ) p/205
* Industrial . all the way !!
• Socket outlets supplying caravan pitches should be ( To BS-EN 60309-2 & IPX4 in accordance with BS-EN 60529 ) 708.553.1.8. p/191
* Industrial types .
• In a room containing a sauna , what additional protection is required ( RCD )
* The Godfather of additional protection .

This One is a Good Learning Curve : 703.411.3.3.
Additional protection shall be provided for all circuits of the Sauna , by the use of one or more RCDs having the characteristics specified in Regulation 415.1.1. RCD protection need NOT BE PROVIDED for the Sauna Heater unless such protection is Recommended by the Manufacturer , ◄◄

 

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17th Edition :
Phase Conductor : see Line Conductor .!
Line Conductor : A Conductor of an a.c. system for the Transmission of Electrical Energy Other than a Neutral Conductor . A Protective Conductor or a PEN Conductor . The Term also means the Equivalent Conductor of a d.c. System unless Otherwise Specified in the Regulations .

( a PEN Conductor Combines both Protective Earth & Neutral Functions )

On a Low Voltage Domestic Supply to a House you get a Line which is alive and a Neutral which is the Return Wire .
Neutral Conductor : Live Conductor .

~ All Conductors Except the Circuit Protective Conductor are Classed as Live Conductors . in Practice the Neutral is Very near to Earth Potential & therefore sometimes Thought of as Not a Live Conductor . [ Wrong ]
( But if there is a Fault in the Circuit the Neutral can become Live as can Earth ) [ Current Flowing through a Résistance = Voltage ]

 

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mA [ Milliamp = One thousandth of an Amp ]
km [ Kilometre = One thousand metres ]
µv [ Microvolt = One millionth of a volt ]
GW [ Gigawatt = One thousand million Watts .
kW [ Kilowatt = One thousand Watts ]

Alternating Current Circuit Calculations :
In D.C. Circuit is Limited by Résistance .
In A.C. Circuit’s the Current is Limited by Impedance ( Z ) Résistance & Impedance are Measured in Ohms .

For this Calculation . Ohms Law is Used and ( Z ) is Substituted for ( R )
( U/Z = I or Voltage ( U ) ÷ Impedance [ Ohms ]
= Current [ Amperes ]

• The Voltage Applied to a Circuit with an Impedance of 6Ω . is 200 Volts . Calculate the Current in the Circuit ?
[ U/Z = I ] 200 ÷ 6 = 33.33A .
• The Current in a 230V Single Phase Motor is 7.6A . Calculate the Impedance of the Circuit ?
[ U/I = Z ] 230 ÷ 7.6 = 30.26Ω
• A Discharge Lamp has an Impedance of 265Ω and the Current Drawn by the Lamp is 0.4A . Calculate the Voltage ?
[ Z/I =U ] 265 x 0.4 = 106 Volts .
• The Current through an Impedance of 32Ω is 8A . Calculate the Voltage Drop across the Impedance ?
[ U = I x Z ] = 8 x 32 = 256V .
• The Current through an Electric Motor is 6.8A at 230V . Calculate the Impedance of the Motor ?
[ U = I x Z ] ( Transpose for Z ) ↔ Z = U/I . = 230 ÷ 6.8 = 33.82Ω .
• An A.C. Coil has an Impedance of 430Ω . Calculate the Voltage if the Coil Draws a Current of 0.93A ?
[ U = I x Z ]
= 0.93 x 430 = 400V

* Calculate the Inductive Reactance of a Coil which has an Inductance of 0.03 henrys when Connected to a 50Hz Supply ?
[ XL = 2πfl ] = 2 x 3. 142 x 50 x 0.03 = 9.42Ω .
* Calculate the Inductive Reactance of a Coil . when Connected to a 60Hz Supply ?
[ XL = 2πfl ] = 2 x 3. 142 x 60 x 0.03 = 11.31Ω . it can be seen from this Calculation that the Frequency Increases the Inductive Reactance will also Increase .
* An Inductor is Required to Cause a Voltage Drop of 180 Volts when a Current of 1.5Ais Passed through it at a Frequency of 50Hz :- Calculate the Value of the Inductor ?
[ UL = I x XL ( this is Ohms Law with Inductive Reactance instead of Résistance )
Transposed : [ U/I = XL ] 180 ÷ 1.5 = 120Ω . XL = 2πfl ↔ 120 = 2 x 3. 142 x 50 x L .
Transposed : 120 -------- ( 2 x 3. 142 x 50 ) = 0.381H . [ On Calculator enter 120 ÷ ( 2π x 50 ) = answer 0.382H )

PS. A Big Thank You would be Nice Amber

 

[Spudnik]

In response to Ambers signing off above, it would be appreciated if all who read the thread use the "Thanks" button, even if it is just on individual posts that you have found helpful. Its not much to ask, and wont take a second to do.

Amber spends a LOT of time compiling and posting information for us all to benefit from and is totally UNPAID for his work.

Thank you Amber..... You are a goldmine.

 

[amberleaf]

Cables for Fixed Wiring . [ am using the Term Fixed for Understanding ] House Bashing Yeah
Cable has Solid Cores ( Conductors ) and thus Doesn’t bend ( i.e. it isn’t a Flexible Cord ) it is Used in Places where it won’t be Moved once it is Installed .
Flexible Cords ( Flexes ) Connecting Electrical Appliances to the Mains Via Plug . Stranded [Flexible ]

Number of Cores .
Three-Core flex is Used on Appliances needing an Earth [ Usually Metal Cased Appliances ]
Two-Core Flex is Used for Double Insulated Appliances [ Look for the Double Insulated Symbol ]

 

[amberleaf]

After Midnight 2.02 minutes past . 4

• How do we most commonly obtain safe working voltages when working on a Construction site ? [ Using a Transformer ] 110V .
* The orange and yellow boxes .
• A device that is designed to switch off an item of equipment foe maintenance comes under the definition of ? [ Isolation ]
* So it can’t be accidentally switched on
• Steel wired Armoured cable is fixed and Supported by means of ? [ Cleats ]
* Clips don’t support . you should use larger types .
• Use of tools on a Construction site supplied by an employer are covered by ? [ PUWER ]
* Comes under Equipment . ]
• The most appropriate method for ensuring accessory boxes are installed level is by using ? [ A spirit level ]
* The good old fashioned . available in many sizes .
• When cleaning up after fixing equipment to concrete structures . you should be cautious of ? [ Dust ]
* What does drilling concrete produce .
• One major danger of using extension leads on a Construction site is ? [ Cutting through the flex ]
* Maybe machinery rolls over it or .
• When considering working on a live installation , what should first be done ? [ A Risk Assessment ]
* Assess the dangers and possibilities and reduce .
• Ladders should be set on an angle and conform to which of the following RATIOS ? [ One for every 4 Up ] Big / H&S ◄◄ CSCS.
* 75° ◄◄
• What is the maximum lifting weight recommended by the HSE for a fit Male ? [ 25kg ] PS. No jokes Please .
* At waist level it’s .
• An 110V transformer designed to be used on a Construction site is Centre Tapped for additional ? [Give 55V to Earth ]
* Reduce voltage to earth .
• Particular care should be taken when using soldering irons that the ? [ Lead has not been burned or damaged ]
* it get Hot .
• The use of Grinding Equipment is covered by the ? [ Abrasive Wheels Regulations ] ◄◄
* Think about how they work .
- Electricity at Work Regulations . N/A.
- COSHH Regulations . N/A.
- IEE Wiring Regulations . N/A.
• What is the most likely outcome of poor manual handling techniques ? [ Back ]
* Keep the …. Straight all the time .
• it is recommended that screwdrivers and certain hand tools are insulated to ? [ 1000V ]
* VDE insulated
• A light switch is defined as circuit ? [ Control ] as we kwon the 17th Edition . Functional ◄◄
* On and Off .
• The type of accident that kills most Construction workers is ? [ Working from Height ] ◄◄ -&-s / CSCS
* Falling . Dropping .
• A battery forms part of a simple electrical system and is commonly known as the ? [ Source ]
* Right at the start .
• The correct method of fixing surface socket outlets to concrete walls is to use ? [ Woodscrews and expanding plugs ]
* Standard red/brown types & screws .
• The fixing of termination lugs onto copper cables should be performed using ? [ A crimping tool set at the right conductor size ]
* Any type of device that performs the correct function
• Surface conduit is fixed and supported by the means of ? [ Saddles ]
* should be the shape of the conduit and planned and fixed beforehand .
• The best method of fixing surface sockets to metallic stud walling is the use of { Spiral plasterboard fixings ]
* Think fast and convenient .
• Before we begin work on an installation , we need to check what surfaces we will be fixing to this information may most likely be found in the ? [ Specification ]
* Should detail all the information about an installation .
• Before using , a ladder must be in inspected by ? [ The intended user ]
* Hopefully you before you get up there .
• Electrical operated power tools should be ? [ Checked before and after use ] -&-s H&S - CSCS.
* Better safe than sorry .
• All electrical related hand tools should ? [ Undamaged and fit for intended purpose ]
* Do what they are meant to do .
• Before performing a manual handling task . what is the first thing you should ? [ Assess the whole task ]
* Look at the big Picture .
• Completed work at the end of an electrical installation is recorded on ? [ as fitted drawings ]
* Tells you where things are .
• When using soldering items . care should be taken ? [ Against toxic fumes ]
* Melting metal gives off what .
• To reduce financial losses and inconvenience from the theft of tools and materials we should be ? [ Stored in a Locked container ]
* Security is all .