Swa bonding, what method.

[Jason Shawcross]

Hi all

Just need your advice, theirs a discussion going on atm on site between a couple of sparks. We have around 50 apartments being fed by 3core swa from a panel room all glanded into the top of a run of trunking, armour isn't used as cpc. One spark is saying we need to run individual 16mm earth's to each gland
Another is saying 10mm to the first of each set and then looping. I would have thought just bonding the trunking near the board adding some bonding tags in-between the trunking sections and bolting the banjos on would suffice. Tbf the trunking is <o.o1 atm anyway to met. So what's your opinion and regs if possible, don't have book with me.

Thank you.

 

[Wilko]

If it's not a cpc then it just requires supplementary bonding to earth

Good point
I'm just thinking during the masonry drill attack the armour may be called upon to act as cpc so beef it up ?

 

[Leesparkykent]

The banjos don't even need to be linked together if glanded into a bit of steel trunking that's earthed.

 

[Ian1981]

Good point
I'm just thinking during the masonry drill attack the armour may be called upon to act as cpc so beef it up ?

Depends as the steel armour conductivity isn't the same as copper so tho you might use a fly lead of 10mm the armour may not be even that equivalent

 

[westward10]

The banjos don't even need to be linked together if glanded into a bit of steel trunking that's earthed.

Reg 543.2.7 rather clouds all this.

 

[Ian1981]

I link them anyway, just one of those things I like to do.

 

[Ian1981]

Reg 543.2.7 rather clouds all this.

What is the jist of it without me getting off me couch and actually reading it?

 

[Leesparkykent]

Here..I wouldn't class trunking as an accessory though.

 

[Ian1981]

Here..I wouldn't class trunking as an accessory though.

View attachment 37222

Na that's if you use conduit say as the cpc and you take a fly lead from the metal back box to the socket as the conduit is the cpc.
In this case the trunking is not acting as a cpc it mearly becomes an exposed conductive part because the swa is glanded to it.

 

[Wilko]

Depends as the steel armour conductivity isn't the same as copper so tho you might use a fly lead of 10mm the armour may not be even that equivalent

Agreed.
OP scenario of 16mm is a waste of copper imho

 

[Leesparkykent]

Na that's if you use conduit say as the cpc and you take a fly lead from the metal back box to the socket as the conduit is the cpc.
In this case the trunking is not acting as a cpc it mearly becomes an exposed conductive part because the swa is glanded to it.

exactly my thoughts or using 2core SWA and the armour as the CPC.

 

[Deleted member 9648]

The armouring of a SWA is a conductive part not an extraneous conductive part. It will require neither bonding or supplementary bonding as some on here have stated.

 

[Ian1981]

Of course it needs to be earthed.
As it's an exposed conductive part who actually said it needs bonding as in extraneous??
I said supplementary bonded to earth or ' earthing ' which is different to protective bonding ,as in extraneous parts

 

[Bobster]

People don't gland it to the board enclosure because they are too lazy to find a simple solution to do so, just leave it floating in the cavity no one will know is the remit these days.

Thing is, even if the armour isn't being earthed at both ends. It still needs glanding. It needs terminating correctly!

I'd sack any "electrician" who thought this was a solution.

An westwood, I'm not saying you think this is correct.

 

[Dave OCD]

I'd use Piranha type earthing nuts on all the SWA glands rather than banjos with loads of drilling and nuts/bolts.

 

[westward10]

Thing is, even if the armour isn't being earthed at both ends. It still needs glanding. It needs terminating correctly!

I'd sack any "electrician" who thought this was a solution.

An westwood, I'm not saying you think this is correct.

Don't think it is correct at all but it is the nature of the trade now because people do not have skills to engineer solutions.

 

[Deleted member 9648]

Of course it needs to be earthed.
As it's an exposed conductive part who actually said it needs bonding as in extraneous??
I said supplementary bonded to earth or ' earthing ' which is different to protective bonding ,as in extraneous parts

Earthed agreed. But the use of the term bonding in this sort of thing is the cause of much confusion. It results in people assuming a bonding conductor is there to earth their pipes....such confusion causes many a newbie Electrical Trainee bursting with self importance to berate a plumber for using plastic fittings on copper pipes

 

[Bobster]

Don't think it is correct at all but it is the nature of the trade now because people do not have skills to engineer solutions.

It's not following the regs though, everything should be suitably terminated (or words to that effect).

Maybe it's just me, but there seems to have been a huge influx on a few forums all with similar questions. god knows whats going on.

 

[westward10]

It's not following the regs though, everything should be suitably terminated (or words to that effect).

Maybe it's just me, but there seems to have been a huge influx on a few forums all with similar questions. god knows whats going on.

Couldn't agree more Rob.

 

[timbobelfast]

Hi all

Just need your advice, theirs a discussion going on atm on site between a couple of sparks. We have around 50 apartments being fed by 3core swa from a panel room all glanded into the top of a run of trunking, armour isn't used as cpc. One spark is saying we need to run individual 16mm earth's to each gland
Another is saying 10mm to the first of each set and then looping. I would have thought just bonding the trunking near the board adding some bonding tags in-between the trunking sections and bolting the banjos on would suffice. Tbf the trunking is <o.o1 atm anyway to met. So what's your opinion and regs if possible, don't have book with me.

Thank you.

Personally I would use Piranaha nuts (think they do a 32mm size) on each SWA and verifiy that the trunking is solidly bonded. No need for daisy chain links IMHO. What size are the subs?

 

[Deleted member 9648]

Personally I would use Piranaha nuts (think they do a 32mm size) on each SWA and verifiy that the trunking is solidly bonded earthed. No need for daisy chain links IMHO. What size are the subs?