New sub board for shed swa advice.

[Gavin John Hyde]

"I am planning of running a swa fed from 32a mcb from the main board to a sub board." ????

@sparksburnout makes the case for the prosecution

 

[johnduffell]

earthing the armour at the downstream end is OK but it would slow down the disconnection time for faults near the origin. and hopefully no extraneous conductive parts in the outbuilding?

@netblindpaul since you pressed Disagree, I'm looking forward to your explanation or edit did you mean you have to earth from the head end?

 

[netblindpaul]

@netblindpaul since you pressed Disagree, I'm looking forward to your explanation or edit did you mean you have to earth from the head end?

Yes, you must connect the SWA to the installation earthing system at the supply end.
You should see that when you do your design FMEA.

 

[Octopus]

Yes, you must connect the SWA to the installation earthing system at the supply end.
You should see that when you do your design FMEA.

Reg number please

 

[johnduffell]

Yes, you must connect the SWA to the installation earthing system at the supply end.
You should see that when you do your design FMEA.

I'm not an electrician but do you mean the physical connection must be at the supply end, or just that the armour has to be connected to the earthing system that protects it?
I guess you're suggesting if the cable is cleanly cut quickly enough (5s disconnection time) it may leave an unprotected live conductor physically separated from the cpc that protects it, and possibly shorted to the now floating armour.

 

[netblindpaul]

Reg number please

Regulations 3, 4, 7, 8, & 9

 

[netblindpaul]

I'm not an electrician but do you mean the physical connection must be at the supply end, or just that the armour has to be connected to the earthing system that protects it?
I guess you're suggesting if the cable is cleanly cut quickly enough (5s disconnection time) it may leave an unprotected live conductor physically separated from the cpc that protects it, and possibly shorted to the now floating armour.

One potential failure mode yes.

 

[Octopus]

Regulations 3, 4, 7, 8, & 9

That I simply do not believe .....

 

[Dave OCD]

There are occasions when earthing the armour [when a seperate cpc exists in the cable] can only be carried out at the 'load' end and I can't see any reason why this is detrimental to safety when done correctly. I wish people would stop posting misleading nonsense.

 

[sparksburnout]

There are occasions when earthing the armour [when a seperate cpc exists in the cable] can only be carried out at the 'load' end and I can't see any reason why this is detrimental to safety when done correctly. I wish people would stop posting misleading nonsense.

What are these occasions then?

 

[netblindpaul]

That I simply do not believe .....

Look them up then.

 

[Octopus]

Look them up then.

Can’t this week as my regs book is at home BUT the numbers you quote are not actual regs, they are sections

So best you be a little more constructive with you input ......

 

[netblindpaul]

Can’t this week as my regs book is at home BUT the numbers you quote are not actual regs, they are sections

So best you be a little more constructive with you input ......

No Murdoch they are real Regulations, not clauses.
If you have access to the internet, which you obviously do, then you can look this up.

 

[Octopus]

No Murdoch they are real Regulations, not clauses.
If you have access to the internet, which you obviously do, then you can look this up.

What absolute carp.

Proper regs numbers to back up your somewhat dubious claims please

Or do we need a new rating “fake reg”

 

[netblindpaul]

What absolute carp.

Proper regs numbers to back up your somewhat dubious claims please

Or do we need a new rating “fake reg”

Murdoch they are proper regulation numbers, you are now just showing your ignorance.
BS 7671 is not the be all and end all.
These are the Regulations that you will be prosecuted under.
BS 7671 is your Regulation 29 defence if followed.

 

[Octopus]

Murdoch they are proper regulation numbers, you are now just showing your ignorance.
BS 7671 is not the be all and end all.
These are the Regulations that you will be prosecuted under.
BS 7671 is your Regulation 29 defence if followed.

Regulations in what publication ..... Jackanory?

 

[netblindpaul]

Regulations in what publication ..... Jackanory?

Try the LAW.

 

[Octopus]

Try the LAW.

Hum ...

I think you need to calm down and go back and answer the original point again.

There is no law stating that swa must be earthed at the supply end ...

The question was what is the BS 7671 reg number that you believe refers this to

 

[ferg]

Gawd this is like watching an impending train wreck.

 

[netblindpaul]

Hum ...

I think you need to calm down and go back and answer the original point again.

There is no law stating that swa must be earthed at the supply end ...

The question was what is the BS 7671 reg number that you believe refers this to

No your question was, what REGULATION, you actually said in post #23 "Reg number please"
Which I then gave you and since then you have been disagreeing with me.
You said NOTHING about BS 7671, you asked for a Regulation, not a clause in a standard.
Remember, Regulations are law, BS 7671 is a standard.
The numbers I quoted are the law that you would be in breach of.
Try THE, Electricity At Work Regulations 1989 (As Amended).
Also if you want clauses from some industry guidance try...
522.6.201, .202, .203, .204
522.8.10
543.3
IET GN8 guides you to EAWR on this topic just for your guidance.