Does this setup contravene any regs or is it ok?

[DPG]

I don't understand how it contravenes the regulation you stated. You did attempt to explain based around the cable being the origin.

And that's when the argument petered out somewhat.

 

[johnduffell]

No one has really explained how spurring at the mcb is any different from spurring anywhere else. If that appears in the regs then i would be in agreement that it wasn't allowed.

 

[DPG]

No one has really explained how spurring at the mcb is any different from spurring anywhere else. If that appears in the regs then i would be in agreement that it wasn't allowed.

Exactly. A feed may be taken from the OCPD. Same circuit.

 

[markythesparky]

Yep. I can’t go through it all again. It’s not well written but I believe the intention of the reg is as I have tried to explain.

Your argument gains ground if you take the reg literally but it is not what the schemes mentioned believe it to mean. Neither do I.

Us Sparks like to deal in black and white, we don’t like grey. It confuses us. Me included. But the regs are full of grey. And they are non statutory which clouds the grey even more.

In fact 120.3 and 133.1.3 specifically allow you to depart from BS7671 albeit with special consideration.

So you cannot take every part of BS7671 literally, although in a court of law you may well persuade the prosecutor by your argument. But then again you may not, because decisions made in a court of law are also not black and white.

I would personally err on the side of my assessing body until I’m told otherwise. I don’t see the point in the risk.

Getting back to the OP’s original decision, (which now seems an eternity away) what was wrong with having two spare ways anyway? I stand to be educated here but which reg states that there should be more than two spares on a 23 way CU?

 

[Marcus Vaughan]

Clash of the Titans' anyone?

 

[Silly Sausage]

It contravenes 314.4!!!!!!!!!

No it doesn't.

The pertinent part of 314.4 is: "The wiring of each final circuit shall be electrically separate from that of every other final circuit, so as to prevent the indirect energizing of a final circuit intended to be isolated. "

Meaning, in my view, that there is NO electrical connection, in any shape, form or other, to another set of wiring fed from any another OCPD.

As has been repeatably said, a circuit wiring can take almost any form you want, within reason!

 

[SparkyChick]

The only section I believe that talks about future proofing is this:-

132.3 Nature of demand
The number and type of circuits required for lighting, heating, power, control, signalling, communication and information technology, etc. shall be determined from knowledge of:
(i) location of points of power demand
(ii) loads to be expected on the various circuits
(iii) daily and yearly variation of demand
(iv) any special conditions, such as harmonics
(v) requirements for control, signalling, communication and information technology, etc.
(vi) anticipated future demand, if specified.

I've always considered leaving spare ways as good practice and I usually aim for 25% of live ways as spare at the end of a job.

 

[Silly Sausage]

Clash of the Titans' anyone?

https://www.google.com/url?sa=t&rct...=Lvcnx6-0GhA&usg=AOvVaw01S1ATxuoj_SOJVSsL-oIu

 

[markythesparky]

The only section I believe that talks about future proofing is this:-

132.3 Nature of demand
The number and type of circuits required for lighting, heating, power, control, signalling, communication and information technology, etc. shall be determined from knowledge of:
(i) location of points of power demand
(ii) loads to be expected on the various circuits
(iii) daily and yearly variation of demand
(iv) any special conditions, such as harmonics
(v) requirements for control, signalling, communication and information technology, etc.
(vi) anticipated future demand, if specified.

I've always considered leaving spare ways as good practice and I usually aim for 25% of live ways as spare at the end of a job.

As have I but even from that reg, leaving spare ways in a CU is not a specific requirement.

OP has installed a massive 23 circuits CU and had 2 spare. But he decided wanted one more. It wasn’t necessary and if he’d had left it at two spares this thread wouldn’t even exist.

All because of an unnecessary risk.

 

[SparkyChick]

As have I but even from that reg, leaving spare ways in a CU is not a specific requirement.

No it's not and this comes up from time to time. My view is better to leave some spare... how many times have you been to a job wanting just one breaker and there is nothing

I know eventually the spares may be used, but that takes time.

OP has installed a massive 23 circuits CU and had 2 spare. But he decided wanted one more. It wasn’t necessary and if he’d had left it at two spares this thread wouldn’t even exist.

I think I would have contented myself with two.

No, it wouldn't, but as I've said it's interesting to see other peoples perspectives on the regulations even if you don't agree with them.