SWA Depth

[homernumber1]

New to this forum but can anybody give me the exact depth that SWA Cable should be buried at only figure i can find in 7671 is 600mm but it also says its up to situation.So is it all down to interpretation.

 

[Silly Sausage]

And what would be the best method for your known earth?

 

[Knobhead]

I’d normally be working from a switch room or substation so the MET would be to hand. That is working on the assumption that the MET is reliable. As that would be one of the first things to be tested I think I’d trust it.

 

[Bobster8]

Should be at least 500mm if buried also use a yellow tape with danger electricity on it above
Sometimes cleating along a wall is an easier option.

 

[Bobster8]

earth spike

 

[Engineer54]

In fact, any reading between earth and the isolated steel wire armouring will indicate a sheath failure!!
As Tony stated, size length of the run could cause an absorption value to be shown, but that isn't going to be a problem on domestic installations.

Any earth reference should be sufficient to conduct a sheath test, i've even used temporary spikes, and found compromised cable sheaths.

 

[kingeri]

I've been at a job recently where the SWA to the garage had been run along the wooden fence. Fence had blown over and was in bits...only the SWA was actually half holding it together.

 

[Octopus]

I've been at a job recently where the SWA to the garage had been run along the wooden fence. Fence had blown over and was in bits...only the SWA was actually half holding it together.

Hum, attached to a fence - not to be recommended!! lol

 

[Marvo]

As I’ve only done it on new cables (that I can remember) I would be looking for >500M Ώ. But you’ve got to allow for cable size and length and also allow for charging time as with any decent cable run.

We've always worked on >100MΩ @ 1000v for <100m cable length. There's no hard and fast rule or figures in our regs, this was just a figure I was recommended by the cable manufacturers many years ago and we've just stuck with it ever since.

 

[tidyboiler]

Have a weekend away trip to the seaside with TB and dig his trench for him.

He won't take me away for a weekend......................... :sad_smile:
good job I have a reserve. :love:

 

[Geordie Spark]

I'll admit I've never been taught a sheath test. How do you do one?

Unroll it and blow in the open end - like you would a balloon. If it leaks air, don't use it.