cabling swa to cu from outhouse

[ColinJacobson]

The time delay will not stop it tripping if the fault in the outbuilding is a neutral one and the breakers there are SP.

That's only a problem if he installs SP RCBOs as protection. Colin/OP is describing an RCD in the outhouse, so if if that said RCD is a DP RCD acting as the main switch then there will be none of the problems you describe.

Exactly!

 

[ColinJacobson]

That's only a problem if he installs SP RCBOs as protection. Colin/OP is describing an RCD in the outhouse, so if if that said RCD is a DP RCD acting as the main switch then there will be none of the problems you describe.

Quite. Good to see that some people are confident of their knowledge

..and some are not.

 

[ban-all-sheds]

Strange how you didn't challenge what I said then, if you knew it was wrong, given how you're trying to wriggle out of answering other things.

Missing two opportunities to pick me up on that does seem to me to be highly inconsistent with your behaviour so far, and I'd be surprised if it didn't seem that way to a lot of others too.

Anyway - if you're confident of your own knowledge, will you please explain the following:

• What the obvious reason is for having an RCD protecting armoured cable.
  
• Which regulation(s) require such an RCD.
  
• How preferring an RCD in a separate building is compliant with 314.1 (i).
  
• What types of fault a 100mA delayed RCD at the house will clear, and who and/or what will be protected against what risks by doing that.

Thanks.

 

[ColinJacobson]

Strange how you didn't challenge what I said then,

Stop wriggling. The options were given. Take your choice.

 

[ban-all-sheds]

Options?

Do you mean the 3 you listed here?

If so, I don't recall you asking for people to choose between them, I only saw you stating your opinions of each, stating what your preference was, and subsequently ignoring every request for you to explain why you had the opinions you did and why you thought that your preferred option complied with the regulations.

So it's hard to see how I can be accused of "wriggling", but if you do want me to choose between your 1-3 my answer is "none of them".

Stop wriggling.

That should work both ways, shouldn't it?

• What is the "obvious reason" for having an RCD protecting armoured cable?
  
• Which regulation(s) require such an RCD?
  
• How is having an RCD in a separate building compliant with 314.1 (i)?
  
• What types of fault will a 100mA delayed RCD at the house clear, and who and/or what will be protected against what risks by doing that?
  
  

 

[1john]

I gave the options given by a superb elec engineer to th e same scenario.

No you didn't, you gave the option of an idiot, who cannot seem to construct a simple circuit to an out building. Seeing as you decided that this advice was worthy of passing on and that you believe that this "designer" is superb, I am of the firm beleif that you must stop giving bad and poor advice. You are in no position to do so, you have no real idea of the regulations and each of the topics you start is as alarming to read as the next.

The reason for having an RCD is not obvious, it is an option that should be avoided at all costs in order for the circuit to comply with BS-7671, try reading it some time

An RCD is another buildind leaves you in this situation - a fault on one circuit causes all circuits to fail, better still, the device that fails isn't even in the same building. A 100mA time delayed RCD does NOT make this comply.

 

[ColinJacobson]

I gave the options given by a superb elec engineer to the same scenario.

No you didn't, you gave the option of an idiot, who cannot seem to construct a simple circuit to an out building. Seeing as you decided that this advice was worthy of passing on and that you believe that this "designer" is superb, I am of the firm beleif that you must stop giving bad and poor advice.

I am of the belief that he is superb and you give bad advice.

Three options. Take your choice.

 

[ColinJacobson]

scenario 1 - why is it a negative to have an SWA cable without an RCD protecting it??

Imagine a spade or fork through the cable in an outhouse shorting live to earth.

 

[Chri5]

Regs suggest 600mm + for cable in u/g. I didn't think spades were that long

So what do you suggest the DNO's do with supply cables on the street and in to houses ?

 

[ban-all-sheds]

Imagine a spade or fork through the cable in an outhouse shorting live to earth.

Is it OK if I also imagine the fault loop impedance being OK and the circuit OPD operating?

 

[ban-all-sheds]

Regs suggest 600mm + for cable in u/g.

And cable markers/warning tape etc.

 

[Chri5]

 

[ban-all-sheds]

That's a US table...

 

[ColinJacobson]

Regs suggest 600mm + for cable in u/g. I didn't think spades were that long

By me in the 2002 house, the cable to the detached garage drops out of the side of the house about 1 metre from the drive way and drops down. A car could easily hit it.

 

[ColinJacobson]

Imagine a spade or fork through the cable in an outhouse shorting live to earth.

Is it OK if I also imagine the fault loop impedance being OK and the circuit OPD operating?

Spot sqirming.