SWA not earthed

[nrg]

Hi All

I need some advice, I have been to look at a job for a mate who has moved into a new house.

Basically he wants a new garage cu installing.

There is a 4mm 3 core SWA going from a 32amp mcb in the house but the swa amour has not been connected to earth and the armour strands have been removed!

Is there a way I can get an earth on the armour at the head end? At the garage end it has not been connected and there is a seperate earth rod for use in the garage.

Any help would be appreciated

 

[Andy™]

re-termiante the end properly

 

[nrg]

Explain please, do you mean run a new cable?

 

[Andy™]

remove end from connection, re-termiante properly

 

[NozSpark]

Terminate te end into an adaptable box with a gland and extend the cables into the CU

 

[Electroglow]

Could u use the earth core in the garage cu and earth that end of the SWA???? Any regs broken?? Only a thought

 

[Andy™]

Any regs broken??

yes. it needs earthed at the start. otherwise how would ADS work

 

[Electroglow]

Surely if the SWA runs to the garage and one of the 3 cores is a earth and is connected to the main CU then that earth would run to the garage cu could he not earth that end of the SWA sheath??

I would re terminate in to a a box as said above. But sometime it may not be possible

 

[NozSpark]

Surely if the SWA runs to the garage and one of the 3 cores is a earth and is connected to the main CU then that earth would run to the garage cu could he not earth that end of the SWA sheath?? I would re terminate in to a a box as said above. But sometime it may not be possible

Ok then, terminate the gland into a conduit coupler and bush that into the CU if only an inch short!

If it's a fair bit shorter then extend the SWA using a galv thru box, some crimps and glands!

 

[nrg]

Thanks for your suggestions I'll get it sorted ASAP.

I didn't know if there was some kind of band that could be used like a bonding clamp to achieve this. What do distributors use on TNS systems where the lead sheeth is the means of earth?

 

[samson337]

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[Electroglow]

I have seen that used before but on older install seen it once when they tryed to extend SWA. I think it was just normal earth strap clamp

 

[Andy™]

Thanks for your suggestions I'll get it sorted ASAP.I didn't know if there was some kind of band that could be used like a bonding clamp to achieve this. What do distributors use on TNS systems where the lead sheeth is the means of earth?

constant force spring. its also used in resin joints to hold the braid to the armour

 

[Sidewinder]

You however, must NEVER use a BS951 clamp on an SWA, or concentric cable, in fact, any cable.

 

[loaded]

Earth the SWA at the garage end.

Perfectly acceptable IMO.

No point in making hard work of it.

ANd its better than nothing at all.

 

[Sidewinder]

Loaded,

I have to disagree.

The fundamental principle of ADS requires the supply cable to be earthed at the origin with this kind of supply & cable.

Think about the fundamental principles, science and engineering, the function of ADS, what you are trying to achieve etc, then think about the possible failure modes of the earth at the "far" end of the supply and how this would affect the disconnection under fault conditions.

 

[NozSpark]

He can't earth it from the garage end,,,, its TT'd there:O

 

[Sidewinder]

Noz,

Missed the TT bit!

I only read the last post as I "thought" I had read the rest of the thread!!!

In which case the cable must be earthed supply end if you are splitting the earthing systems.

I'll go and re-read the thread.

 

[Electroglow]

Re: SWA not earthed

Surely if the SWA runs to the garage and one of the 3 cores is a earth and is connected to the main CU then that earth would run to the garage cu could he not earth that end of the SWA sheath?? ????????

 

[Sidewinder]

No he can't connect the sheath to the cpc at the load end.

I'm gonna re-read the whole thread now...