swa bonding

mamba · Dec 3, 2009

Work on a job where the pulled in 4 core 50mm swa [TP + n] with a seperate 35mm main earth. Does the swa still need to be bonded ie 10mm brass screw bolting down banjo together with a lugged 10mm cpc from banjo to MET. I say yes as I feel the armouring within the swa still needs to be earthed however supervisor claims not required any answers or references to clear this up.

peteludman · Dec 3, 2009

mamba said:
Work on a job where the pulled in 4 core 50mm swa [TP + n] with a seperate 35mm main earth. Does the swa still need to be bonded ie 10mm brass screw bolting down banjo together with a lugged 10mm cpc from banjo to MET. I say yes as I feel the armouring within the swa still needs to be earthed however supervisor claims not required any answers or references to clear this up.

oh yes it dose you have to earth the steal wire the niceic would tell you that the told me

Mr Mark Sparks · Dec 3, 2009

it doesnt need a fly lead back to the met just a banjo and a bolt (also if you want fly lead to earth bar)

Guest123 · Dec 3, 2009

Yes.

You still need to supplementary bond the armouring even if it's not being used as a CPC.

roukel01 · Dec 3, 2009

If the board that the SWA is glanded into is painted or powder coated, it requires a fly lead from the banjo. You cannot assume an adequate earth through a nut and bolt if the board is coated in some way, and therefore a fly lead is required, you cannot also 'scrape' the paint off so that the banjo is in contact with metal, because this compromises the protectiveness of the coat that the manufacturer pu on it, and so a fly lead is needed. Anyway, without being technical, lets face it, how long does it take to put a fly lead in??
If however, it's glanded off to an earth trunking system, then no, no fly lead.

peteludman · Dec 3, 2009

Mr Mark Sparks said:
it doesnt need a fly lead back to the met just a banjo and a bolt (also if you want fly lead to earth bar)

no i dont think so mate i have done a lot of work on this subject.

what if the metal box or DB gets rusty and you get high continuity on the banjo then somone damages the swa and touch steal wirs to phase conductor and it dont blow fuse the the glands and steal wire will be live .

i know this is unlikley to happen but it can.

Davey101 · Dec 4, 2009

I'm with Marksparks on this (just my opinion though

)

Phil Mumford · Dec 4, 2009

I am under the impression that a metal covering of a live cable will be earthed at the supply end. As above the best method of doing this is a banjo and flylead.

Out of interest, what size earth would you run?

Those new earthing nuts look the business....anyone used them yet?

Sintra · Dec 4, 2009

Those new earthing nuts look the business....anyone used them yet?[/QUOTE]

Used them a couple of times glanding SWA's into PVC enclosures made earthing a very simple job.