testing assessment

[james king]

i know, but i like to gather as much info as poosible. as i did course about 2yrs ago n for got it all.

as for rcd protection what are the main 4 times u need it as i was told again by a nic bloke to rcd or crbo every thing?

 

[acat]

additional protection is always a 30mA RCD
cables less than 50mm in wall and not protected by steel conduit
in a bathroom
TTsystems

Im sure you can think of more



Chris

 

[james king]

i have a re wire for him to look at in a flat but also my 2nd job is a garage wire all in pvc conduit he said he only wants one job to see but if he was to come to the garage would he look at the spacing of the saddles ?

 

[acat]

Dont concern yourself with minor details the number one concern is are you SAFE and is the work you have done SAFE spacing if incorrect to my knowledge is not a fail just an observation so whatever you do be safe in action and thought. and providing you can answer most of the questions either of the top of your head or find it in the OSG you should be ok.

The isolation procedure of which there are many varities boil down to what I have given you that you need to know of by heart.



Chris

 

[james king]

Dont concern yourself with minor details the number one concern is are you SAFE and is the work you have done SAFE spacing if incorrect to my knowledge is not a fail just an observation so whatever you do be safe in action and thought. and providing you can answer most of the questions either of the top of your head or find it in the OSG you should be ok.

The isolation procedure of which there are many varities boil down to what I have given you that you need to know of by heart.



Chris

the only problam is i do not have a proving unit or lock off kit. every thing else i have. i think i will get them asap. i think i worrying bout detail alot but i will lose a lot of money and contracts if i dont get it lol that y i am worried, i am even in talks with the local council. although i admit i do not know every thing to do with electrical and probally need to know alot more as i state in previous post but i can only learn, i no saprk who have 25 yrs expericance and no nothing about testing or regs but evey thing is neat and tidy and get it done fast. u have been very helpfull acat very much apprecaited thnak u

james

 

[Sintra]

What are your disconnection times for circuits on different systems ie TT TNS TNCS.
Do you need to earth a metal back box.
What is basic protection.
What is fault protection.
What are the zones in a bath or shower room.
What are exposed and extraneous conductive parts.

1.
230v final circuits in a TN system not rated greater than 32A must disconnect within 0.4 seconds under fault conditions. 411.3.2.2

230v final circuits in a TT system not rated greater than 32A must disconnect within 0.2 seconds under fault conditions. If disconnection is made by a fuse or mcb and all extraneous conductive parts are connected to the main equipotential bonding then disconnection times that are applicable to TN systems may be used. 411.3.2.2

Under fault conditions in a TN system, final circuits over 32A and distribution circuits must disconnect within 5 seconds. 411.3.2.3

Under fault conditions in a TT system, final circuits over 32A and distribution circuits must disconnect within 1 second. 411.3.2.4

2.
Metal back boxes only need to be earthed if there is no fixed lug in back box or you are using a steel conduit etc as a cpc.

3.
Basic Protection is protection against electric shock under normal operating conditions. p4, p20

Fault Protection is protection against electric shock with regard to a failure of basic insulation. p4, p24

4.
Zone 0 for a bathroom is the area inside the bath. 701.32.2Zone 0 for a shower room is the area inside the shower basin. If there is no shower basin, zone 0 is 10cm high from the finished floor level and extends to 1.2m around the fixed shower head. 701.32.2

Zone 1 for a bathroom is the same width as zone 0 (the width of the bath) extending to 2.25m above the finished floor level. 701.32.3Zone 1 for a shower room is 2.25m from the finished floor level or the height of the fixed shower head from the finished floor level if more than 2.25m, and the width of the shower basin. If the shower has no basin then zone 1 extends to 1.2m around the fixed shower head. 701.32.3If the space under the bath or shower basin is accessible without the use of a tool it is classed as zone 1, otherwise it is not considered to be a zone. 701.32.3

Zone 2 for a bathroom is the same height as zone 1 (2.25m) extended to 0.6m around the bath. 701.32.4Zone 2 for a shower room is the same height as zone 1 extended to 0.6m around the shower basin. If there is no shower basin zone 2 is replaced by zone 1 extended to 1.2m around the fixed shower head. 701.32.4

5.
An Exposed Conductive Part is a metal part of electrical equipment which can be touched and which may become live in the event of a fault. p24All exposed-conductive-parts of a TN installation must be connected to the main earthing terminal.

411.4.2Exposed conductive parts of less than 50mm2 are exempt from fault protection.

410.3.9An Extraneous Conductive Part is a metal part that is not part of, but in proximity to the electrical installation and is liable to introduce earth potential. p24

All extraneous conductive parts in an installation must be connected to the main earthing terminal by main protective bonding conductors. This applies to the metallic sheath of a telecommunications cable where permission from the owner of the cable must be obtained. 411.3.1.2

 

[james king]

1.
230v final circuits in a TN system not rated greater than 32A must disconnect within 0.4 seconds under fault conditions. 411.3.2.2

230v final circuits in a TT system not rated greater than 32A must disconnect within 0.2 seconds under fault conditions. If disconnection is made by a fuse or mcb and all extraneous conductive parts are connected to the main equipotential bonding then disconnection times that are applicable to TN systems may be used. 411.3.2.2

Under fault conditions in a TN system, final circuits over 32A and distribution circuits must disconnect within 5 seconds. 411.3.2.3

Under fault conditions in a TT system, final circuits over 32A and distribution circuits must disconnect within 1 second. 411.3.2.4

2.
Metal back boxes only need to be earthed if there is no fixed lug in back box or you are using a steel conduit etc as a cpc.

3.
Basic Protection is protection against electric shock under normal operating conditions. p4, p20

Fault Protection is protection against electric shock with regard to a failure of basic insulation. p4, p24

4.
Zone 0 for a bathroom is the area inside the bath. 701.32.2Zone 0 for a shower room is the area inside the shower basin. If there is no shower basin, zone 0 is 10cm high from the finished floor level and extends to 1.2m around the fixed shower head. 701.32.2

Zone 1 for a bathroom is the same width as zone 0 (the width of the bath) extending to 2.25m above the finished floor level. 701.32.3Zone 1 for a shower room is 2.25m from the finished floor level or the height of the fixed shower head from the finished floor level if more than 2.25m, and the width of the shower basin. If the shower has no basin then zone 1 extends to 1.2m around the fixed shower head. 701.32.3If the space under the bath or shower basin is accessible without the use of a tool it is classed as zone 1, otherwise it is not considered to be a zone. 701.32.3

Zone 2 for a bathroom is the same height as zone 1 (2.25m) extended to 0.6m around the bath. 701.32.4Zone 2 for a shower room is the same height as zone 1 extended to 0.6m around the shower basin. If there is no shower basin zone 2 is replaced by zone 1 extended to 1.2m around the fixed shower head. 701.32.4

5.
An Exposed Conductive Part is a metal part of electrical equipment which can be touched and which may become live in the event of a fault. p24All exposed-conductive-parts of a TN installation must be connected to the main earthing terminal.

411.4.2Exposed conductive parts of less than 50mm2 are exempt from fault protection.

410.3.9An Extraneous Conductive Part is a metal part that is not part of, but in proximity to the electrical installation and is liable to introduce earth potential. p24

All extraneous conductive parts in an installation must be connected to the main earthing terminal by main protective bonding conductors. This applies to the metallic sheath of a telecommunications cable where permission from the owner of the cable must be obtained. 411.3.1.2

thankf for your answer. very well explaned. the only thing im still confused about is back box earthing i have been told by a nic contractor not to do it. but for metal clad boxes i do. but not in domestic standered back boxs.??

 

[Sintra]

There is no reg to earth back boxes with a fixed lug unless using a conduit or a cable sheath as a cpc. I just do it as it is good practice and only takes a few seconds.

 

[D80]

Who is your assessor from Napit? We had Richard Cunningham, very nice gentleman but he knew his stuff as well. Found him thorough but fair, they want the qualified guys and not the cowboys.

 

[james king]

clifford brown his name is. any know of him?