RCD Protection

[AndyPRK]

Odd, I thought those all came with an RCD.

If you have 4 spare ways you could fit two RCD's in there, assuming you have two seperate netural blocks.

 

[GaryMo]

Which he won't have as it's a bog standard Wylex NH1404 14 way consumer unit with a 100A switch.

 

[2352]

basically the switch top right is a double pole switch, meant to switch both live and neutral.

In your case only the live is switched. The neutral is run through that little box to the left of the switch.

It seems odd that they would supply that box to do this, when it'd be easier to run the neutral through the switch.

Theres nothing wrong with just switching the live, in fact, most installations dont even have this isolation switch, so cound yourself lucky.

An RCBO replaces the individual circuit MCBs, which for you would require 10 of them, at a cost of about £300 in materials alone.

A real bodge and not in compliance with th 17th edition, would be to replace the mainswitch with an RCD. But this is ugly and causes lots of nuisance trips.

A compromise, but might cost you the same as RCBOs in the end, is to replace that whole unit with a split load board, with two RCDs.

this was crystal clear, thanks for it
I wld need to know this becuase ...here it goes:
I fully rewired my flat in jan 2008 as part of a flat upgrade. Warrant was obtained in oct 2007. However the electrician (select registered!) who did the job disappeared and never released a certificate. I stupidily left it till now when I'm urged by the Council to get a sign off of the flat. I explained the Council that i was never given a certificate however they seemed quite understanding and asked for a PIR instead, which i had few days ago. In the certificate is stated that the system is satisfactory but not fitted with a RCD system. I don't know to be honest if the Council will pass it, thats why i'm getting ready in case of a warrant fail...

 

[GaryMo]

It's a report, not a certificate and all they will be interested in is the word 'satisfactory'.

 

[bd3cc]

I would make the main switch(top right) double pole, by taking the existing neutral to it, and adding a neutral tail to the CU.
Remove the existing Main switch from the CU and replace with a 63A/30mA rcd, get a 17th edition conversion kit for the CU, add another
RCD, and neutral bar, and the board would then be, I believe fully 17th edition compliant, and all circuits would be RCD protected.
I would think that 2 rcd's and a conversion kit would be cheaper than a large number of RCBO's.
An RCBO can replace an MCB, but protects only the circuit to which it is fitted, and are expensive. I think your CU is WYLEX, so you would need a WYLEX RCBO as they are not always compatible between the makes.
HTH
bd3cc

 

[bongos]

These are RCBO's. They combine the function of an RCD and an MCB in one. The advantage being that an earth fault on a circuit will only trip the RCBO protecting it.

If you had a RCD protecting a 'bank' of circuits (as would be the case with a split load board) then you would loose all the circuits until the earth fault had been located on a specific circuit. This can be extremely frustrating if it is a difficult to locate, intermittent fault.

As already suggested - look at RCBO's for your socket circuits and electric shower too (if you have one). The downside with RCBO's is they are a little on the pricey side...

 

[GaryMo]

Remove the existing Main switch from the CU and replace with a 63A/30mA rcd, get a 17th edition conversion kit for the CU, add another
RCD, and neutral bar, and the board would then be, I believe fully 17th edition compliant, and all circuits would be RCD protected.

Replace the main switch with an RCD? Where will the second RCD be fed from? Surely not the first? It's normal practice to have a main switch within the consumer unit which supplies two RCD's.
What's you're proposing sounds like a balls up!

 

[2352]

These are RCBO's. They combine the function of an RCD and an MCB in one. The advantage being that an earth fault on a circuit will only trip the RCBO protecting it.

If you had a RCD protecting a 'bank' of circuits (as would be the case with a split load board) then you would loose all the circuits until the earth fault had been located on a specific circuit. This can be extremely frustrating if it is a difficult to locate, intermittent fault.

As already suggested - look at RCBO's for your socket circuits and electric shower too (if you have one). The downside with RCBO's is they are a little on the pricey side...

Thank u very much for it! Will this fit my CU type/model?

 

[bongos]

I fully rewired my flat in jan 2008 as part of a flat upgrade. Warrant was obtained in oct 2007.

As long as your council is happy with the fact it was wired to the 16th edition then I can't see any problems anyway. They must be aware that the work started pre regulation change (July 2008) so hopefully it won't be a problem. The installation is just not to current regs that's all - apart from that it is satisfactory.

 

[bongos]

Thank u very much for it! Will this fit my CU type/model?

http://www.tlc-direct.co.uk/Main_Index/Consumer_Units_Index/Wylex_Ns_2/index.html

These will yes. Scroll down to the very bottom. You will require B-type RCBO's for a domestic setting like a flat.

 

[bd3cc]

It is acceptable to have an external main switch, and a conversion kit,(MK do them) would provide 2 seperate neutrals to the RCB's. All 17th edition CU's have internal neutral and live tails feeding 2 rcd's.

 

[GaryMo]

As long as your council is happy with the fact it was wired to the 16th edition then I can't see any problems anyway. They must be aware that the work started pre regulation change (July 2008) so hopefully it won't be a problem. The installation is just not to current regs that's all - apart from that it is satisfactory.

He'll probably have a number of code 4's relating to lack of RCD protection but these alone won't result in a non-satisfactory report.

 

[GaryMo]

All 17th edition CU's have internal neutral and live tails feeding 2 rcd's.

Yes they do, from an integrated main switch.

 

[2352]

Thank u very much for it! Will this fit my CU type/model?

http://www.tlc-direct.co.uk/Main_Index/Consumer_Units_Index/Wylex_Ns_2/index.html

These will yes. Scroll down to the very bottom. You will require B-type RCBO's for a domestic setting like a flat.

That's cool! So, one of these for each of the socket circuits, that right? (i don't have an electric shower).

 

[Monkeh]

Thank u very much for it! Will this fit my CU type/model?

http://www.tlc-direct.co.uk/Main_Index/Consumer_Units_Index/Wylex_Ns_2/index.html

These will yes. Scroll down to the very bottom. You will require B-type RCBO's for a domestic setting like a flat.

That's cool! So, one of these for each of the socket circuits, that right? (i don't have an electric shower).

An expensive solution for a problem which doesn't exist.