CU Change Testing

[Retroelectric]

Hi all.
Did an EICR today on a rented property that had a CU change about 8 years ago.
Found a few things wrong, the main issue really is that a few sockets are fed in 1.5 from the ring and a couple of wall lights are fed of the ring as well in 1.5.
Just wondering how much testing you guys do after or before a CU change? IR and closed rings and visually looking at bonding, cpc's present, rubber etc as not everyone will pay for a pre-change EICR.
If you're doing an install and do the end to end from the CU and the cross connection, and the readings are going to pass, would you drop any of the socket plates for a visual inspection?

 

[Pete999]

Hi all.
Did an EICR today on a rented property that had a CU change about 8 years ago.
Found a few things wrong, the main issue really is that a few sockets are fed in 1.5 from the ring and a couple of wall lights are fed of the ring as well in 1.5.
Just wondering how much testing you guys do after or before a CU change? IR and closed rings and visually looking at bonding, cpc's present, rubber etc as not everyone will pay for a pre-change EICR.
If you're doing an install and do the end to end from the CU and the cross connection, and the readings are going to pass, would you drop any of the socket plates for a visual inspection?

Always do an EICR before a CU change to help avoid my backside getting bitten after the change.

 

[Dartlec]

Hi all.
Did an EICR today on a rented property that had a CU change about 8 years ago.
Found a few things wrong, the main issue really is that a few sockets are fed in 1.5 from the ring and a couple of wall lights are fed of the ring as well in 1.5.
Just wondering how much testing you guys do after or before a CU change? IR and closed rings and visually looking at bonding, cpc's present, rubber etc as not everyone will pay for a pre-change EICR.
If you're doing an install and do the end to end from the CU and the cross connection, and the readings are going to pass, would you drop any of the socket plates for a visual inspection?

If changing CU then I try to do an effective EICR beforehand, though don't always tell the client that's what's happening.

If R1+R2 is fine at every socket, I won't always drop socket plates, especially if they are painted in, etc. I'd be much more likely to if the property was older than 60s and there was a chance of rubber cabling around.

I will usually check lights more carefully, especially any that look suspiciously DIY added...

There is a whole best practice guide on changing a Consumer Unit which details the minimum that should be done and doesn't mention dropping sockets.

Of course a single spur socket could in theory be run in 1.5mm if all necessary requirements are met (no derating, etc - which might be unlikely to be fair), I believe it used to be specifically mentioned as a possible allowed method in an older version of the OSG?

 

[loz2754]

1.5mm spurs are mentioned in the diagram in appendix 15.

 

[pc1966]

1.5mm feeding a single socket or FCU is fine, but I would not encourage its uses as single sockets often get changed for double with little concern for what is feeding them.

 

[DefyG]

would you drop any of the socket plates for a visual inspection?

That would depend on your sample rate % agreed with the client beforehand

 

[loz2754]

1.5mm spurs are mentioned in the diagram in appendix 15.

I just checked Appendix 15.
1.5mm spurs are only permitted via a FCU.

 

[Dartlec]

I just checked Appendix 15.
1.5mm spurs are only permitted via a FCU.

I have a feeling it might have changed in recent editions, or more specifically that in a previous version of book or OSG it was less clear that it had to be a Fused Spur.

Possibly in the 16th, which is what I first trained in, though can't see anything from a quick skim - just a vague memory.

Though really no good reason for not using 2.5 in any case these days - just that there might have been a time when it was arguably "compliant" - surface clipped short run with no derating to single socket, for example...