Adding RCD protection to obsolete MCBs

[IAmSparkytus!]

Best way to add RCD protection to specific circuits in an old Siemens DB which I’m told is now obsolete.

Install an additional enclosure adjacent to the DB to hold new RCBOs and feed these from the obsolete MCBs?

Any other ideas?

 

[buzzlightyear]

New tails to new consumer unit rcd from there or sub to the rbo incloser and rbo from there.

 

[ipf]

Recommendation for a board change, maybe?.....perhaps what buzz is hinting at.
Domestic or what?

 

[pc1966]

Install an additional enclosure adjacent to the DB to hold new RCBOs and feed these from the obsolete MCBs?

If doing a 2nd DB then just put in a RCD and use the appropriate MCB.

But really it might be netter to consider a new CU that has available RCBOs. It would only take a couple of circuit "upgrades" to make the overall cost (parts and labour) of CU change less than modifying circuits each time.

 

[IAmSparkytus!]

Commercial

Customer has handed me an EICR with lots of C1s and C2s recommending RCD protection for socket outlets and circuits marked up as bathroom heaters etc. Looking for a quote to fix all.

Issue is it wouldn’t be 1 board change, it would be approximately 15 due to circuits in question being fed from multiple boards.

Have never carried out remedial work for someone else’s EICR. Is it down to us to decide whether these works even need carried out to start with or if the customer wants it fixed is that a good enough reason to quote?

They’ve C1 or C2d a socket having only 1 socket screw so it already sounds questionable in my head!

 

[timhoward]

Have never carried out remedial work for someone else’s EICR. Is it down to us to decide whether these works even need carried out to start with or if the customer wants it fixed is that a good enough reason to quote?

In practical terms you have a choice of either:
a) fixing at least every C1 and C2, and preferably writing a covering letter describing the remedial work (I include photos) so the customer can prove the work has been carried out. If something is plainly wrong explain this in the letter quoting regs OR
b) convincing the customer it is more cost effective to start again with a new inspection.

Personally I'd be honest with the customer that in my opinion some of the "potentially dangerous" things are not really so in terms of electrical safety, even if they are a really good idea.

 

[ipf]

Commercial

Customer has handed me an EICR with lots of C1s and C2s recommending RCD protection for socket outlets and circuits marked up as bathroom heaters etc. Looking for a quote to fix all.

Issue is it wouldn’t be 1 board change, it would be approximately 15 due to circuits in question being fed from multiple boards.

Have never carried out remedial work for someone else’s EICR. Is it down to us to decide whether these works even need carried out to start with or if the customer wants it fixed is that a good enough reason to quote?

They’ve C1 or C2d a socket having only 1 socket screw so it already sounds questionable in my head!

Thought it would be commercial.
It sounds questionable, for sure.
What do you mean....C1 or C2d a socket......is it C1 or C2?......or is it more than one item?
You could look at RCD sockets for the power circuits, if the installation's decent.
Costs a fair bit but nothing like DB replacements. It also gives you individual isolation on tripping, rather than full circuit.
I'd be making my own decision on the condition whilst doing the remedials, or maybe even prior to starting. A quick inspection of the reported observations and recommendations shouldn't take too long.
Then, if you get to know the job and feel confident enough about it, have a word with the customer/client about what you feel.
It may work out well for both of you.

 

[pc1966]

They’ve C1 or C2d a socket having only 1 socket screw so it already sounds questionable in my head!

Hmm, not looking good on the "they know what they are talking about front".

C1 is for immediate danger, so exposed live parts (or incorrect polarity at CU) where a simple mistake is fatal.

C2 for sockets without RCD should, to me, follow the BPG#4 advice which is basically C2 for high risk areas such as outdoors or bathroom, and C3 for other areas. Typically commercial/industrial sites have better (or even just "a") PAT testing policy so plugged in stuff is probably lower risk than homes so I don't see much reason to divert from BPG#4 on that aspect.

Of course without seeing the site and its usage you can't really tell, but that is not a convincing start if they have not explained the reasons for the coding here.

 

[IAmSparkytus!]

Planning on quoting to complete the works as asked by the customer and if they go ahead, once the works are complete I’ll send them a formal email/written letter advising that work has been carried out to satisfy the C1 and C2s as per the test sheet but still can’t guarantee the installation is in a “satisfactory” condition as we didn’t carry out the initial EICR.

Must be about 20 items on the EICR advising that MCB needs upgrading to RCBO or RCD needs installed for circuit(s).

For some of the boards this will only be 1 circuit but for others it will be 2, 3, 4 or even 5.

will look at it again tomorrow but the plan as it stands is to disconnect the relevant circuits from the current DBs, use the existing MCBs to feed an RCBO in an enclosure adjacent to the boards and then supply the circuits from the RCBOs

Anything wrong with the above?

 

[Lucien Nunes]

use the existing MCBs to feed an RCBO in an enclosure adjacent to the boards and then supply the circuits from the RCBOs

Why RCBO and not just RCD? You'll still have protection from the original MCB.

 

[IAmSparkytus!]

I was thinking about the width of 2P RCDs and how the enclosures would need to be larger. Only have limited space adjacent to each DB.

 

[pc1966]

I was thinking about the width of 2P RCDs and how the enclosures would need to be larger. Only have limited space adjacent to each DB.

That is one reason, another that I wondered is if the new compact RCBOs are cheaper than RCD? Not really a big factor here compared to the time.

 

[IAmSparkytus!]

Is there an obligation to have a main switch ahead of the RCBOs in the enclosure?

 

[pc1966]

Is there an obligation to have a main switch ahead of the RCBOs in the enclosure?

I don't think so. There has to be some means of isolation, but given the main board can perform that and it is adjacent to your proposed add-on I would think that is sufficient.

Proper labelling is a must though! Few folk ever read the site documents that might have modifications and gotcha! points listed...