2391 for a Sunday morning.

[La Poste]

A three phase 400/230V electrical installation within a ten year old commercial unit for sales and storage of medical equipment forms part of a TN-C-S system and is to be inspected and tested. Ze was measured as 0.09 Ohms.

Following a small fire in the office area three lighting circuits and three ring final circuit require re-wiring. On completion of the work the client requires all relevant documentation for the installation for insurance purposes.

The existing metal clad TP & N distribution board contains BS EN 60898 type B and C
circuit breakers.
The existing surface mounted wiring system consists of 70C thermoplastic insulated
single core cables in metal conduit and trunking in the warehouse area.
Plastic conduit and trunking is used in all the other areas.

The new lighting circuits are wired in 1.5mm single cores 70C thermoplastic insulated cables.
The new circuits are 18, 24 and 32 metres in length respectively.
The resistance per metre for a 1.5mm single conductor is 12.10 mOhms/M.

State giving reasons the documentation to be competed for the work stated above.

I was thinking six minor works certificates for the three lighting and ring circuits because they are not new circuits they are re-wired old circuits and they would most likely follow the same route as the old cabling and be wired in the same size cable.
The method of fault protection would be the same.
Then a PIR for the rest of the installation.

What do you think?
Gracias.

 

[malcolmsanford]

A three phase 400/230V electrical installation within a ten year old commercial unit for sales and storage of medical equipment forms part of a TN-C-S system and is to be inspected and tested. Ze was measured as 0.09 Ohms.

Following a small fire in the office area three lighting circuits and three ring final circuit require re-wiring. On completion of the work the client requires all relevant documentation for the installation for insurance purposes.

The existing metal clad TP & N distribution board contains BS EN 60898 type B and C
circuit breakers.
The existing surface mounted wiring system consists of 70C thermoplastic insulated
single core cables in metal conduit and trunking in the warehouse area.
Plastic conduit and trunking is used in all the other areas.

The new lighting circuits are wired in 1.5mm single cores 70C thermoplastic insulated cables.
The new circuits are 18, 24 and 32 metres in length respectively.
The resistance per metre for a 1.5mm single conductor is 12.10 mOhms/M.

State giving reasons the documentation to be competed for the work stated above.

I was thinking six minor works certificates for the three lighting and ring circuits because they are not new circuits they are re-wired old circuits and they would most likely follow the same route as the old cabling and be wired in the same size cable.
The method of fault protection would be the same.
Then a PIR for the rest of the installation.

What do you think?
Gracias.

The clues are in the question, now what do you think .

 

[La Poste]

Got that one wrong I guess.
Maybe I got hung up on notification of a new circuit, you know Part P.
Where they say a new circuit does not have to be notified as long as the cable travels the same route and has the same current carrying capacity.

Work that is non notifiable:
Replacing the cable for a single circuit only, where damaged, for example by fire, rodent or impact.

So an electrical installation certificate is still issued for the re-wire of a circuit that has been damaged by fire but the work is not notifiable.

Ok?

 

[Deleted member 9648]

Got that one wrong I guess.
Maybe I got hung up on notification of a new circuit, you know Part P.
Where they say a new circuit does not have to be notified as long as the cable travels the same route and has the same current carrying capacity.

But it doesnt come under part P....it's commercial.


As far as I can see one EIC would cover all,unless a PIR is asked for there is no reason to carry one out.

Edit...just re-read the first part and it seems a PIR is requested.

 

[La Poste]

Excellent.
Thanks for that.
Sunday morning, still got to get my brain in gear.

 

[firemanowl]

It's a commercial unit so part p doesn't apply.

 

[IQ Electrical]

Forget Part P anyway, it doesn't exist as far as the 2391-10 is concerned (and 99% of the population).

This is a very common scenario question, there's often an existing installation and some new works.

The answer as you now know is an EIC, a PIR, 2 SOTR and 2 SOI.

Apologies for the abbreviations, not setting a good 2391-10 example, pc down for 2 days now, doing everything on iPhone...

 

[gap30]

me too mate been looking over some stuff for a couple of hours this morning

3 things i am getting wrong repeatedly and its very frustrating

state the effect on insulation resistance/conductor resistance when

circuit lenth increases/decreases csa increases etc

also have i got this one right - the breaking capacity of the circuit breaker must be greater or at least equal to the prospective fault current

and finally ip codes - where is the list in the regs

ipxxb - finger contact only
ip4x - 1mm diameter
ip2x - foreign or solid objects up to 12.5 mm

what is the meaning of x in ip8x or whatever

there is no specific meaning for x relating to ?

 

[SirKit Breaker]

An Electrical Installation Certificate, schedule of inspections, and a schedule of test results for the new works carried out.

A Periodic Inspection Report for an Electrical Installation, schedule of Inspections, and a schedule of test results for the existing installation.

6 items = 6 marks.

Cheers............Howard

 

[SirKit Breaker]

me too mate been looking over some stuff for a couple of hours this morning

3 things i am getting wrong repeatedly and its very frustrating

state the effect on insulation resistance/conductor resistance when

circuit lenth increases/decreases csa increases etc

also have i got this one right - the breaking capacity of the circuit breaker must be greater or at least equal to the prospective fault current

and finally ip codes - where is the list in the regs

ipxxb - finger contact only
ip4x - 1mm diameter
ip2x - foreign or solid objects up to 12.5 mm

what is the meaning of x in ip8x or whatever

there is no specific meaning for x relating to ?

GAP, with regard to increase in circuit length and effect on resistance etc, I am not going to tell you the answer. You are an Electrician and this is basic electrical principles, and i know that you know the answer.

You are correct about the protective device, it must be rated at or higher than the PEFC/PSSC of the installation as determined by measurement or enquiry.

The x in the IP ratings means it doesn't matter what level of iP rating it is for solid or liquid ingress as appropriate depending on the position of the X i.e
IP6X IPX6.

The tables are in the OSG and BRB, you can also get it on google.

Cheers.........Howard

 

[gap30]

conductor resistance is proportional to conductor length
three factors that can affect insulation resistance
condition of installation
circuit length
number of circuits connected in parallel

conductor resistance
conductor temperature
load current

thats what i know of the top of my head

 

[tony mc]

Get to know your IP codes especially IPXXD IP4X IPXXD IP4X they seem to always come up.

Also when a question comes up re Insulation resistance or conductor resistance read them carefully making sure you know what they are asking as its easy to miss read and give the wrong answer and get mixed up between the two!!!!

When you get to the second part of the exam you need to read the question a few times as its easy to go down the wrong track and lose marks. It always looks difficult at first but once you break the question down it gets alot easier especially when you jot down the infomation that they are giving you and then KNOW the actual questions they are asking.


Seems like your getting their with the amount of studying your doing keep it going and good luck!!!!!