Can you sign off any work with a 30ma RCD.

[Johnconnor]

Hi, my question is. If I have an old wylex consumer unit with NB type 2 breakers (not 60898). Or let's say any CU for that matter. If it's protected by a 30ma RCD, will that pass the cert?. Or for example will the use of old mcbs not be up to standard. Thanks

 

[buzzlightyear]

Are you doing a Eicr test?.

 

[Johnconnor]

Are you doing a Eicr test?.

No, new ring has been wired to a new extension at the back of the house and just needs an EIC.

 

[timhoward]

The installation needs to be in a safe condition to extend.
Any new circuits or alterations need to meet latest regulations.
It's theoretically possible to comply using a rewireable board.

Numerous questions come to mind, for for starters:
Where is the RCD installed, between meter tails and consumer unit, or at the start of the new circuit?
Has a surge protection device been installed?
Is the lighting in the extension RCD protected?
Is there a bath or shower room in the new extension?

 

[Johnconnor]

No, new ring has been wired to a new extension at the back of the house and just needs an EIC.

The installation needs to be in a safe condition to extend.
Any new circuits or alterations need to meet latest regulations.
It's theoretically possible to comply using a rewireable board.

Numerous questions come to mind, for for starters:
Where is the RCD installed, between meter tails and consumer unit, or at the start of the new circuit?
Has a surge protection device been installed?
Is the lighting in the extension RCD protected?
Is there a bath or shower room in the new extension?

 

[Johnconnor]

Thanks for the reply This is the puppy, RCD protecting all circuits in the house. Everything past this consumer unit meets regs. If RCD is testing fine and all other tests are fine. Would this be acceptable to sign off, or would most go down the consumer unit change route?

 

[timhoward]

I'd be concerned about the 30A breaker allegedly for upstairs lights? What size is the cable on that circuit?

 

[Johnconnor]

I'd be concerned about the 30A breaker allegedly for upstairs lights? What size is the cable on that circuit?

Good spot, but that's a ring circuit.. needs to be reblabled. Assume every circuit has the correct rating for each cable it's supplying.

 

[Aaron b]

I would suggest that it was upgraded and inform the client that any future work would likely need an upgrade.

 

[Johnconnor]

I would suggest that it was upgraded and inform the client that any future work would likely need an upgrade.

I agree an upgrade would be best in this situation. Just want to know, would this be okay to sign off if the customer really didn't want an upgrade

 

[timhoward]

In general I can't see why under amendment 1 this couldn't be extended. There's a reg recommending dividing the installation to avoid nuisance tripping.
Pragmatically, the RCD is very old and I wouldn't trust it too much. Is this a TT installation?
There's a few reasons I'd rather not, but I don't think I'd be prevented from doing so.

From September (Amendment 2) there would need to be a statement saying no SPD is required, and I'd not be adding a sockets circuit protected by a type AC RCD.

 

[Johnconnor]

In general I can't see why under amendment 1 this couldn't be extended. There's a reg recommending dividing the installation to avoid nuisance tripping.
Pragmatically, the RCD is very old and I wouldn't trust it too much. Is this a TT installation?
There's a few reasons I'd rather not, but I don't think I'd be prevented from doing so.

From September (Amendment 2) there would need to be a statement saying no SPD is required, and I'd not be adding a sockets circuit protected by a type AC RCD.

Thanks for the info. It's a tncs

 

[timhoward]

There's the non-combustible consumer unit question too.

 

[M-B-Electrical-Services]

Ok, so it's a PME supply.

Are the meter tails 25mm and is the earthing conductor 16mm?
Bonding conductors 10mm?

Plastic CU is not an issue unless thermal damage is noticed.

There's also the question of maximum demand of 63A at the RCD being exceeded here.

Lighting - 66% of total current demand for each circuit
Power - 100% of the first ring circuit + 40% of all other circuits
Cooker - 10A + 30% of remaining rated current + 5% if the CCU has a socket outlet
Shower - No diversity allowable
Instantaneous water heater - 100% of largest heater + 100% of second largest + 25% of of any others
Thermostatically controlled water heater - No diversity allowable
Underfloor heating - No diversity allowable

Does the test button on the RCD function ok?
Does the RCD trip within 40ms on a 5x test?
Does the EFLI of each circuit measure below the max zs?
Clearly IR is good on each circuit as you would have nuisance tripping otherwise.

At the end of the day, it is irrelevant what the customer wants. You are the qualified & competent person carrying out the inspection and it's your professional opinion that matters here.

Ultimately, is the electrical installation safe for continued use?

You can run yourself in circles questioning yourself with EICR's.
Take a step back, look at the installation as whole and make a professional judgement based on what you see.

 

[ipf]

There's the non-combustible consumer unit question too.

You don't have to change a plastic CU to install a new circuit, though.

It's not ideal but I feel that if the new installation meets regulation standards it would be OK...as long as the existing installation supply requirements are also up to standard.
Plenty of questions need answering, as you say.