Pub Wiring done wrong?...please read carefully

[Clitheroe]

HI Everybody!!!

Need some help asap really: (sorry what follows is rather long)

Where I work as a KP, the wiring situation is as follows:

Supply comes in, underground cable single phase-looks like TNCS or TNS.

From meter, tails go to Wylex RCD 100ma trip-not time delayed by looks of it- possibly from the 80s if not before according to head chef.

Tails from RCD go to big Henley block.

From Henley block several sets of tails:

1 set to a CU feeding the flat above with 100ma RCD main switch

1 set to a CU feeding other things with mains switch, no RCD at all

1 set feeding a Wylex switchfuse with fuse feeding cellar CU marked 'SUB MAINS TO CELLAR'

1 set feeding another Wylex 2 way CU, not sure what though.

Cellar CU is Proetus with RCD main switch and another CU directly joined on to it? This had a 30ma RCD in it and since a good few months someone from Robinsons Brewery has fitted a 100ma Wylex RCD (different brand!) in place of the 30ma due to nuisance tripping by what I've been told!!!!

About 20 MCBs in the cellar CUs altogether!

No 30ma RCDs anywhere and the CUs in question supply ground floor sockets!!! and were fitted about five years back.

Had tripping on kitchen sockets tonight just been and both RCDs in the Proteus and old Wylex both tripped.

I suggested to the owners to get on to the brewery about this since there are RCDs in series and a main one not possibly needed now that trips the entire building?

Can anybody else on this shed some light please since a few things here seem wrong to me?

 

[plugwash]

It seems like there are two issues here.

The first is the lack of discrimination, one fault could easilly trip that main RCD and take out everything.

The second is that 30ma RCD protection for sockets is lacking. According to the 16th edition this should be provided for sockets that can reasonablly be expected to supply equipment outside the equipotential zone and according to the 17th edition it should be provided for all sockets intended for general use and with a current rating below some value (I think it's either 20A or 32A, I'm not sure though).

I would think the main RCD should go and all the CUs should be replaced with ones with appropriate RCD protection.

 

[Clitheroe]

Thanks very much for your help plugwash.

Regarding the RCDs, this is exactly what happened last night and has happened a few times before. Of course though like I said, somebody they had come round when the owners mentioned the tripping just went and replaced the 30ma with a 100ma RCD!

If somebody is insistent however that a mains RCD remain there then I was thinking a time delayed type be installed in place of the existing one.

 

[ColJack]

since it's a pub, then what equipment is there likely to be used outside?

 

[RF Lighting]

That sound almost dodgy enough to be pub standard wiring

 

[Click-Sure]

I'd advise the owner to ask the brewery for a PIR (Periodic Inspection Report) to be carried out, then you'll know what exactly they are up against. I'm suprised one has not been carried out recently, as it is often a condition of insurance for commercial premesis, especially pubs/clubs.

If nuisence tripping damages the brewerys equipment or loses them revenue, which could potentially happen if problems persist, they'll be very interested. Heath & Safety at work legislation comes into play here too.

RF: My sentiments exactly.
A very high standard of pub wiring even! Its been a long time since I did anything other than drink in a pub, and for good reason, if that oppotunity knocks again I'm definately buying that audible cable finder.

 

[Clitheroe]

since it's a pub, then what equipment is there likely to be used outside?

I can't say for sure, but wouldn't the RCD requirement for ground floor sockets/general use sockets apply here as well or is just for domestic premises? (there is a flat above)

Either way though, the main RCD is a bit of a nuisance tripping the entire building so surely this could be improved I was thinking.

 

[RF Lighting]

Yep, RCDs are required in commercial premisis the same as tey are in domestics.

I spent a couple of years doing pub fitting work, and used to find some very 'interesting' wiring.

 

[ColJack]

there was no requirement for all downstairs sockets to be RCD protected.. it all comes ( or came ) down to those words..

"..reasonably be expected to supply portable equipment for use outdoors.."

if the pub had a garden then it's "reasonable to expect" that a mower may be used outdoors..

if the pub is all tarmac'd up for car parking then there is no "reasonable expectation" for any portable outdoor equipment to be used..

christmas lights may be used, but they don't count as portable.. you don't hold them while they are on..

most domestic sparkies just put the whole downstairs on an RCD because it was easier and cheaper than specific sockets that required it ( such as a socket in a garage or the sockets closest to the back door and front door..