main connection to consumer unit or meter tails

[BruceB]

I had a look at g83/2 and thought it was sufficiently vague that provided:
- there is a downstream mcb to provide overload protection
- the prospective fault current at the downstream mcb was enough to blow the suppliers fuse
then it meets g83/2 and 7671.

But there is a serious risk that a single 2.5mm conductor will not be gripped properly in the input terminals of a standard cu main switch when alongside say a 25mm conductor

 

[wersolaruk]

This really is very bad practise the tails should been spilit through a double pole Henley block which then feeds a 1 way rcd protected or main switch depending upon cable routing and mechanical protection, the circuit would then be fed from 2.5 t+e 16a mcb, this really boils my wee when a total lack of experience or being under pressure to complete job and you have not got a Henley block or tails just sheer laziness in my book. But the customer does not have a clue, would be due to in correct survey.

 

[SPARTYKUS]

I don't understand why this could possibly be argued to be okay.... In the event of a fault (short circuit, overload) the cable will fry. Which bit am I missing?

a solar course?

I understand it is not a normal cable as per a normal CU, in that it is feeding back but it could still, conceivably, by a long shot, be the subject of trauma.

I'm not having a dig, just want to follow

 

[Gavin A]

I don't understand why this could possibly be argued to be okay.... In the event of a fault (short circuit, overload) the cable will fry. Which bit am I missing?

it's a current limited device, so can't possibly overload a correctly sized cable outside of fault conditions (reg 433.3.1 (ii) I think)

the fault current is really the issue here, where in some circumstances the bullet could supply sufficient protection against fault currents (probably not the case with 2.5mm cable, as pointed out above), but the DNO don't allow this as per the G83 regs.

For clarity, I don't think anyone's saying it's ok or good practice, I'm just outlining what the thinking is behind it, and why some sparks might think that it could be allowed if they'd not spotted the line about this in the G83 regs.

 

[Gavin A]

manufacturers instructions would also come in here, as most specify the maximum overload protection device allowed for that inverter.

 

[SolarCity]

I don't understand why this could possibly be argued to be okay.... In the event of a fault (short circuit, overload) the cable will fry. Which bit am I missing?

a solar course?

I understand it is not a normal cable as per a normal CU, in that it is feeding back but it could still, conceivably, by a long shot, be the subject of trauma.

I'm not having a dig, just want to follow

The cable won't fry. The fuse will blow in the event of short circuit.

However, I think most of us would agree that it is very bad practice. As BruceB says, 2.5 in a connection with 16/25mm is incorrect anyway but even so, why not just do the job properly?

 

[Gavin A]

The cable won't fry. The fuse will blow in the event of short circuit.

However, I think most of us would agree that it is very bad practice. As BruceB says, 2.5 in a connection with 16/25mm is incorrect anyway but even so, why not just do the job properly?

yep - it's not as if the customer's paying several thousand pounds for the installation is it... no wait, that's exactly what they're doing, so saving £50 max on a proper garage unit, henley block and tails is taking the **** really.