When to install metal consumer units

[alex kane]

Hi Everyone

I am aware that we now have to install metal consumer units in domestic premises now but at what point should we swap a plastic board over to a metal one?

The reason I ask is I've been to plenty of jobs where there is a plastic CU with no RCD protection. Ideally I would swap the main switch for an RCD but should I also be swapping over the whole CU for a metal one?

What work/ at what point do you say to the customer "you need a new CU" besides when the job is to install a new one obviously? I know I could write a note on my EIC but personally I'd rather not have to do that.

 

[Flanders]

Not sure I would ever just change a main switch with a RCD Unless required for a TT supply.
The only reason that I could see a domestic installation needing upgrading to RCD protection to make the installation safe would be for socket outlet liable to be used outdoors and you could fit an RCBO or RCD sockets for that.

 

[Octopus]

Do you think swapping a main switch for an RCD complies with the regs?

 

[Midwest]

Don't thing the spirit of 421.1.201 requires any replacement of plastic to metal, regardless of how much the inners you replace. That would just be maintenance.

If you replaced the CU because of lack of replacement parts, then that would be the time to apply the reg.

Someone recently posted about moving a CU, i.e. to one side a few inches. That was a lively debate

 

[static zap]

(RCD - for Main switch )...

The disadvantage is being in the dark , actually !

 

[alex kane]

RCCB's that meet BS EN 61008 are rated for isolation so I don't see the problem? I know on a big installation this wouldn't be ideal but say on a CU with four circuits.

 

[Ian1981]

In what context do you require a rcd main switch to replace a main switch isolator?
I.e. What job are you undertaking that requires it?

 

[Octopus]

^^ best you review 314 in the BYB

 

[Risteard]

Do you think swapping a main switch for an RCD complies with the regs?

I would suggest that it can depending on the circumstances. It's certainly not expressly forbidden. A risk assessment would determine whether inconvenience caused was excessive or presented any danger. As someone else mentioned maybe there are only a handful of circuits fed from the DB with other DBs present. Otherwise we would outlaw all instances of using an RCCB to protect more than one circuit which would be a nonsense!

 

[Octopus]

^^ I only raised this as lots of people don't seem to realise that this reg even exists... there are, of course lots of RCBO options .....

 

[alex kane]

The reason I ask this question is because most customers won't pay for RCBO's even when I've explained it's the best option because of the cost. If I'm to do work in their house I need to ensure it's RCD protected to cover my back. Swapping the main switch for an RCD is the quickest/ most cost effective way to do this.

I suppose installing one RCBO for the circuit I've worked on would suffice but it would be better to ensure the whole property has RCD protection. This scenario is where I wasn't sure whether I would have to change the CU to a metal one.

Which reg specifically says you cannot use an RCD as a main switch?

 

[Octopus]

I suppose installing one RCBO for the circuit I've worked on would be the best option as it would NOT be sensible to have the whole property on a single RCD protection. This scenario is where I wasn't sure whether I would have to change the CU to a metal one.

Which reg specifically says you cannot use an RCD as a main switch?

Corrected that for you

You are obviously new to the game ... a RCBO is more than adequate AND then you only need to test / inspect your circuit - install an upfront RCD means you need to test the entire installation too.

As for changing a CU to AMD3 for a new circuit or circuit change - this is NOT the case, and anyone saying this is not being honest.

 

[Ian1981]

The reason I ask this question is because most customers won't pay for RCBO's even when I've explained it's the best option because of the cost. If I'm to do work in their house I need to ensure it's RCD protected to cover my back. Swapping the main switch for an RCD is the quickest/ most cost effective way to do this.

I suppose installing one RCBO for the circuit I've worked on would suffice but it would be better to ensure the whole property has RCD protection. This scenario is where I wasn't sure whether I would have to change the CU to a metal one.

Which reg specifically says you cannot use an RCD as a main switch?

If you are working on multiple circuits which, by the work that has been undertaken require rcd protection ( installed extra sockets, installed new wiring into a bathroom) then if no rcd protection exists to the installation, the client should be notified of what the new works will entail and what requirements/ changes are needed to the installation/consumer unit before work is undertaken.
Individual rcbo s are an option if the existing consumer unit can accommodate.
The consumer unit if changed to allow the multiple circuits worked on rcd protection would then require to be constructed of a non-combustible material ( ferrous)
Installing an upfront rcd protecting the whole installation is generally regarded as poor practice and offers no division of circuits for safety purposes think the regulation has been quoted 314 etc.
One faulty circuit may cause the full installation to disconnect which is a nuisance if anything and highly inconvenient.
If it was an acceptable method the dual rcd consumer units would be irrelevant.
Hope this helps.

 

[alex kane]

I understand it's not always good practice but getting people to pay for a new board/ RCBO's isn't always easy. On small boards with 4 circuits or less I don't see this being too much of a problem. A split load 20 way board would have 10 circuits on 1 RCD each. I don't hear people moaning about that.

I always tell my customers if they need an upgrade. Testing the whole installation is a minor inconvenience to me when we're talking about a safety issue.

All I wanted to know was whether installing an RCD as a main switch was possible and whether the board would require changing.

I think it's obvious from Murdoch's comments he doesn't know a much as he lets on and just likes slamming others comments.

You're never too old to learn

 

[Octopus]

I think it's obvious from Murdoch's comments he doesn't know a much as he lets on and just likes slamming others comments.

Matey ... if you have a house with a 4 way CU or a 20 way CU, adding a single up front RCD will deliver the same result when a fault occurs - EVERYTHING will switch off...

A RCBO will cost less that a RCD and testing ALL the other circuits...... what is there not to understand?