Pub DB change

[ch1cki]

Hi Guys

Issue 1

i am looking at changing the DB's in my friends pub from the old mess that is there are the mo. At the moment it has a existing 3 phase board with 5 submaines in it supply the Toilets, Cellar, Out House, Skittle Alley & Kitchen. When I replace this one where does it leave me with 30mA protection on 1 the submaines that are in 16mm T&E and 2 the circiuts that are off of the boards from the submaines i.e. Toilet circuits etc?

Issue 2

Next to the existing 3 phase board I have about 20 circuits spread across 3 old rewirbe DB's which I am looking to put into a 24way board. Now where does this leave me with 30mA protection? I understand that certain circuits would be advisable to fit RCBO's to showers etc but is it nesassary for the rest seeing that the actual fixed wiring was done pre 17th?


Cheers

Ben

 

[ImpededLoop]

To answer both questions. Any work that you undertake has to meet current regs. Therefore any cable that requires RCD protection will require an RCD.

The twin and earth submains only require RCD protection if buried less than 50mm.

 

[Octopus]

I would be very wary about introducing rcd protection into the pubs I know as most of them have dodgy looking electrics.

rcbo's is the way to go but only after some testing

 

[ch1cki]

How does that stop 12 circuits all going in the kitchen then if I put the submains on a RCBO? Surely those circuits were already installed prior to 17th?

 

[ImpededLoop]

How does that stop 12 circuits all going in the kitchen then if I put the submains on a RCBO? Surely those circuits were already installed prior to 17th?

It doesn't stop you losing all 12 circuits. If you're doing a board change, any circuits on that board need to be fully tested and RCD protection provided where required.

If the 16mm twin and earth cables aren't buried less than 50mm, they don't need RCD's. Either BS7671 or the OSG would be a good reference for you.

 

[Flanders]

Make sure you do a full test before changing dbs. There could be borrowed neutrals and earth leakage on circuits already and by the sounds of it most of the circuits will have to be protected by rcbos so you need to check they all ok first , another option is to rewire sub circuits so they don't nead rcd protection

 

[telectrix]

your problem with fitting RCD protection to the sub-main board feeds is that a fault will take out the whole sub. i'd be checking the installation method of those feeds and making a decision based on how they were installed. a risk assessment on the likelyhood of damage by nails/screws/plumbers etc. could give you the argument for not fitting RCD to the feeds. documentation of reasons why is advised.

 

[ch1cki]

So I either have to re-route the submains if even possible! Or change all the other old Memera 2000 boards or try and find RCBO's, are you kidding me?

 

[ImpededLoop]

Why would you need to change all the other Memera boards? You only need to concern yourself with the circuits that are directly fed from your new board.

However, if you do RCD protect the submains, ensure there are no earth faults on the circuits that the sub boards supply.

 

[shanky887614]

what quals have you got ben, im curious you mentioned 17th and 2391 in another thread?


dont even think of puttingan rcd on supply to boards, you will keep getting called back