Electrical Inspection C1? Really?

[Gary_S]

I failed an electrical inspection with a few C2s and one C1. The C2s are all a bit odd (mostly) but the C1 has me baffled.

The Workshop / Garage is on the other side of a lane to my house. I have an Eton box splitting the supply, 1 to my house CU and 1 to a Wylex Box. The cable is armour-core and runs above and underground, in a hard plastic conduit on the underground part. 1 electrician, the inspector said I need RCD protection, the other 2 said I don't as the Wylex Box below is sufficient.

Please let me know what I need to do.

 

[Myfordman]

I have a vaguely similar installation. Power incomer and meter in a shed in the corner of the field and 300m or so of SWA to the house but all on my land (no public roadway involved).
There is a 100mA time delayed RCD upstream of the SWA and normal 30mA fast RCD in the house.
"normal" faults wont trigger the 100mA RCD which would be a b. nuisance to traipse across the field in the dark to reset but will of course cover any faults in the underground cable.
Whether the 100mA RCD is mandatory I don't know but it seems to make sense.
Do you actually need the electrics inspected? Not normally needed for residential property unless you are renting it out.

 

[Gary_S]

I have a vaguely similar installation. Power incomer and meter in a shed in the corner of the field and 300m or so of SWA to the house but all on my land (no public roadway involved).
There is a 100mA time delayed RCD upstream of the SWA and normal 30mA fast RCD in the house.
"normal" faults wont trigger the 100mA RCD which would be a b. nuisance to traipse across the field in the dark to reset but will of course cover any faults in the underground cable.
Whether the 100mA RCD is mandatory I don't know but it seems to make sense.
Do you actually need the electrics inspected? Not normally needed for residential property unless you are renting it out.

Unfortunately yes, thatched house insurance requirement.

 

[Myfordman]

OK understood.
Fix the C2s then ask the spark who failed it for a quote to bring it up to his RCD requirement and ask the other sparkies for a price for an fresh EICR on the understanding that an RCD will not be needed. compare and contrast etc.

 

[Gary_S]

Some of the C2s are a bit off tbh.
I have plastic water pipes as soon as they are on premise and he wants them earthed?
A second CSU is loose. It is if you yank it as its screwed to plasterboard
The main CSU has a miniscule gap where if you pushed hard, you could get your fingers in

 

[Sideways]

The Wylex box is a metal Amendment 3 compliant type of thing so it was potentially installed subject to the 17th edition wiring regs.
The fuse in your Wylex box is the primary protection.
An RCD would provide additional protection.
As far as I can remember, Yellow book (17th ed) doesn't require additional protection by RCD on final circuits that are run in armoured cable.
If the garage / shed has a consumer unit fitted, then this is a distribution circuit, not a final circuit anyway.
RCD's would be required in the garage consumer unit to protect final circuits that aren't installed in armoured cable or metal conduit.
I'm scratching my head here but there might be a need for RCD protection of the distribution circuit if the earth loop impedance was too high for the Wylex box fuse to trip within the time limit. Your inspector would have done the measurements.

 

[NetBlindPaul]

Post a copy of the EICR suitability redacted for privacy?
There are very few things that merit a genuine C1 code. Mainly exposed live parts.
If the loop impedance is too high for the fuse to disconnect then that a C2.
Scheme rules are such that a C1 cannot be ignored the inspector is compelled to act, either be some sort of temporary remedial work or be issuing a dangerous condition notice to the client on the spot.
If the contractor is a scheme member then he’s likely to be in breach of the conditions for membership.
To accurately code in pictures over the internet is difficult.
Especially without sight of the EICR in full.

 

[Gary_S]

Post a copy of the EICR suitability redacted for privacy?
There are very few things that merit a genuine C1 code. Mainly exposed live parts.
If the loop impedance is too high for the fuse to disconnect then that a C2.
Scheme rules are such that a C1 cannot be ignored the inspector is compelled to act, either be some sort of temporary remedial work or be issuing a dangerous condition notice to the client on the spot.
If the contractor is a scheme member then he’s likely to be in breach of the conditions for membership.
To accurately code in pictures over the internet is difficult.
Especially without sight of the EICR in full.

Earth rod stuff was correct so replaced with new rod and cover.
Water pipes are all plastic. Bond wire was under sink from old plumbing which has gone. Oil boiler was being installed.
Neutral connections DB1 I have no idea but sparky will fix
DB2 was solid according to 2 other electricians, just on plasterboard. Fixed
Tails into DB1m,
Circuits labelled.

C1s CCt 4 has been down graded by replacing MCB. It was the first wired in for lights and I forgot to have it changed.
Rodent damage (I live in a thatch)
I think that is where they come into the house. Hole is 2 inches diameter, was like that when I bought the place 20 years ago. Not sure how to fix.

 

[XTX]

Earth rod stuff was correct so replaced with new rod and cover.
Water pipes are all plastic. Bond wire was under sink from old plumbing which has gone. Oil boiler was being installed.
Neutral connections DB1 I have no idea but sparky will fix
DB2 was solid according to 2 other electricians, just on plasterboard. Fixed
Tails into DB1m,
Circuits labelled. View attachment 116474View attachment 116473
C1s CCt 4 has been down graded by replacing MCB. It was the first wired in for lights and I forgot to have it changed.
Rodent damage (I live in a thatch)
I think that is where they come into the house. Hole is 2 inches diameter, was like that when I bought the place 20 years ago. Not sure how to fix.

Wow, pretty trigger happy with the coding there!

No requirement for RCD protection on the distribution circuit to the garage if it is run in armoured cable. The circuits within the garage will however need to be protected by a 30mA RCD/RCBO.
The fuse in the switch fuse needs to be downrated to suit the size of the armoured cable it is protecting.

No need to bond plastic service pipes unless the metal pipes go into the ground somewhere within the property.

There are a few other things I can comment on but my lunch break is over.

 

[NetBlindPaul]

Earth rod stuff was correct so replaced with new rod and cover.
Water pipes are all plastic. Bond wire was under sink from old plumbing which has gone. Oil boiler was being installed.
Neutral connections DB1 I have no idea but sparky will fix
DB2 was solid according to 2 other electricians, just on plasterboard. Fixed
Tails into DB1m,
Circuits labelled. View attachment 116474View attachment 116473
C1s CCt 4 has been down graded by replacing MCB. It was the first wired in for lights and I forgot to have it changed.
Rodent damage (I live in a thatch)
I think that is where they come into the house. Hole is 2 inches diameter, was like that when I bought the place 20 years ago. Not sure how to fix.

Of what I am able to read (on my phone)
those observations are not a C1 unless the cable shows evidence of thermal damage, in which case it would have to be replaced.
A lack of coordination would “normally” only attract a C2.
I would love to see the BS7671 clause for the lack of ducting on the shower fan illustrating how that makes the electrical installation less safe for continuing use.

 

[MikeJhn]

Obviously a domestic electrical contractor looking for follow on work.