Eicr coding

[ses]

Interesting job doing a massive eicr on a factory
On a lot of the socket circuits the sockets are wired in singles in metallic trunking with the trunking being used as one of the cpc's it appears.

So two things are the trunking is also being used as cpc for lighting and some other circuits

And the drops from trunking to sockets are in plastic conduit with only one cpc in

Ideas on coding the above, can you use trunking to provide earthing for more than one circuit?

Also have quite a few boards and switchfuses fed direct from main switch incoming side i.e twinned with the incoming feed on another board coding ideas ?

 

[hermetic]

OK, difficult, but off the top of my head I would test earth continuity and resistance from each socket back to MET or distribution panel, and if it is within limits It passes. If there is a variation in readings, time to start checking connections, best way is probably to flag it up as potentially dangerous and recommend running a cpc in the trunking.

 

[ses]

Resistance is very low on every circuit major parallel earth paths maybe.
Zs all within as well.
Im more wondering about the 1 cpc on ring when socket circuit drops from trunking to socket outlets?

 

[hermetic]

Hi SES,

"Im more wondering about the 1 cpc on ring when socket circuit drops from trunking to socket outlets?"

I am having a bit of a senior moment with the above statement, can you explain a bit more? How old is the install, and what are the general ambient conditions like. If it is clean dry and warm, it is unlikely to give problems, but persistent ambient moisture plays hell with trunking and vertical conduit drops.

 

[KAS1]

I don't think it would be wise to run a separate trunking for each circuit lol "can you use trunking to provide earthing for more than one circuit?"

 

[ses]

Haha yes amazing constructive answer, what i mean is can the trunking be allowed to provide the cpc for every circuit run within it

 

[KAS1]

Why would you think it cannot?

 

[ses]

Sockets are a ring main 2x line 2x neutral and 2x cpc however the cpc is trunking as one leg and single as the other leg.
Now all the sockets are taken from the metal trunking in plastic conduit so at each socket outlet the is only one cpc not two as no path through the plastic conduit

 

[Deleted member 72666]

Nothing wrong with having metal trunking as a cpc and are you sure the sockets are on a ring as most often they are radials and the 1 cpc would then be a flylead from the skt to the trunking.

 

[ses]

I was asking if it could, if you get a bad joint somewhere between two sections then every circuit will loose its earth path. So for instance i have over 300 circuits

 

[Deleted member 72666]

I was asking if it could, if you get a bad joint somewhere between two sections then every circuit will loose its earth path. So for instance i have over 300 circuits

That's why you have to verify earth continuity!

 

[KAS1]

"And the drops from trunking to sockets are in plastic conduit with only one cpc in" from that statement it reads that each plastic trunking has 1 x cpc (if this was 1 x leg returning to the DB the conduits except the last socket on the ring would have 2 x cpc 1 in 1 out etc " so if only 1 x cpc in each drop what does that indicate to you .................

 

[ses]

Yes however every socket has one cpc in

 

[KAS1]

What is the size of the cpc I the plastic conduit?

 

[ses]

I have continuity on line to line and neutral to neutral and all on 32amp mcbs labelled as rings