What would you code this as.

Raptor0014 · Oct 31, 2021

Doing an inspection and came across this.

Feeds are as follows:

Cutout to Meter - 25mm
Meter to connector blocks - 25mm
Connector blocks to CU’s (2 in the house) 16mm.

So far so good as the cutout is 80A not the 100A it’s labelled as.

My query is the 6mm 3 core XPLE that’s going to an outbuilding.

At the outbuilding end is 2 way CU with a 40 RCD switch and a 16a socket & 6a light circuit.

Now I know the RCD will stop the cable ever pulling more than 40A. But as it’s wired into those connectors it has the potential to pull 80a (in theory).

I’ve coded it as a C2 as to me it’s potentially dangerous given there’s no OCPD protecting the cable from the connector until it reaches the RCD in CU in the outbuilding. It’s been there approx 8yrs according to the owner and there are no signs of thermal issues anywhere at either end. But thought I’d garner opinion from the more experienced/knowledgeable folk on here.

What would you code it as? Or would you deem it safe given the RCD at the other end?

[ElectriciansForums.net] What would you code this as.

hasel5 · Oct 31, 2021

Since when has a RCD given over Current protection ?

freddo · Oct 31, 2021

RCDs don't provide overcurrent protection. There is also exposed single insulation. There is no way this type of installation could be deemed safe. If there were sheathed tails feeding a switchfuse mounted by the meter fitted with suitable overcurrent protection for the distribution circuit, which then fed the (properly glanded SWA) that would be fine.

littlespark · Oct 31, 2021

Gotta love it when someone asks about one issue, and the photograph they supply shows a number of others.

Apart from what was mentioned about an rcd not being an over current protection device….. how do you know that the fuse in the cutout is only 80A without pulling it?

hasel5 · Oct 31, 2021

Think my concern is in the Ops post and asking the question to start
Is the Op actually a electrician ?

Taylortwocities · Oct 31, 2021

hasel5 said:
Think my concern is in the Ops post and asking the question to start
Is the Op actually a electrician ?

If he is then he certainly shouldn’t be undertaking test and inspection.
Sorry @Raptor0014 but you’ve a huge hole in your knowledge.

DefyG · Oct 31, 2021

Job to tell, but looking at the tails if the larger ones are 25sq the others look more like 10sq!

Taylortwocities · Oct 31, 2021

DefyG said:
Job to tell, but looking at the tails if the larger ones are 25sq the others look more like 10sq!

About 4 C2 to write up, just for the termination of that SWA.

DefyG · Oct 31, 2021

Agreed the conductors of the armoured look even smallerthan the meter tails ..... Yes C2

Taylortwocities · Oct 31, 2021

DefyG said:
Agreed the conductors of the armoured look even smallerthan the meter tails ..... Yes C2

And cable not supported, nor properly glanded, armour not earthed. Single insulated conductors not in an enclosure…

So many sins in one photo. Love to see the other end of the SWA.

Electrics · Oct 31, 2021

I understand the difference between MCB's and RCD's and what they are supposed to do, but this has raised a question for me.

If RCD's only detect earth leakage what is the amp rating for? If you've got a 40a RCD and for argument's sake no MCB's and just connected something pulling 50a on the load side of the RCD, what would happen?

littlespark · Oct 31, 2021

The 40A marked on an rcd is simply what it is designed to handle.
The same as a simple light switch is rated at 10A… doesn’t turn off at 10A.

Taylortwocities · Oct 31, 2021

Electrics said:
If RCD's only detect earth leakage what is the amp rating for? If you've got a 40a RCD and for argument's sake no MCB's and just connected something pulling 50a on the load side of the RCD, what would happen?

The 40A is thd maximum current that the RCD contacts have been tested to handle reliably. If you put 50amps through it then the contacts could burn out or (worse) weld together. Then the supply will not cut should an earth fault trips the RCD.
The circuit needs current limiting at the source to protect the cable itself and anything else downstream.

Electrics · Oct 31, 2021

I'm also very confused by the thread.

Why would you C2 a circuit for having the potential to pull higher amperage? Wouldn't we then just condemn every installation with 100a cutout since the lights and sockets the tails feed are wired in 1.5 and 2.5mm and so could 'potentially pull 100a'?

Lost.

Electrics · Oct 31, 2021

littlespark said:
The 40A marked on an rcd is simply what it is designed to handle.
The same as a simple light switch is rated at 10A… doesn’t turn off at 10A.

Ah i see thanks.

What would you code this as.

Raptor0014

hasel5

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freddo

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littlespark

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hasel5

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Taylortwocities

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DefyG

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Taylortwocities

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DefyG

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Taylortwocities

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Electrics

littlespark

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Taylortwocities

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Electrics

Electrics

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