Earthing conductor size

[dimmer]

Sizing Earthing conductor


This is the cable from the supply cable (SWA) to the MET ( an earth block)


Clamp is a Bs 951 earth clamp - not acceptable on lead, is that still the case on SWA?

Cable looks to be 4mm2 but could be 6mm2

Now I understand that this is nothing to do with me and I should not touch it.

Length of cable 20cm being its a clamp its easy enough to change. Would you?
I am presuming clamping onto SWA is safer than clamping onto lead?

How would the DNO terminate the EC.

Is the cable big enough though

1361 fuse 60 A

TNS

Ze 0.10

Disconnection time 0.1

230/ .10=2,379

2379x2379 = 5,659,641 x 0.1 = 565,961 sqroot =752 /115 = 6.5 mm2


Is that correct.

The low Ze would suggest a good earth Correct?

but this good earths low Ze gives a high fault current

which gives a lower disconnection time, which will push up the size of the cable needed?
Eh!
I've confused myself

 

[riveralt]

Sizing Earthing conductor
This is the cable from the supply cable (SWA) to the MET ( an earth block)
Now I understand that this is nothing to do with me and I should not touch it.

So the question must be asked why are you then?

How would the DNO terminate the EC.

Get them in to show you how.

I've confused myself

This is that self preservation element in all of us saying stop and get the DNO in.

 

[EFLImpudence]

230/ .10=2,379

It doesn't get much easier.

That's the trouble with calculators

 

[dimmer]

indeed

 

[JohnW2]

Nonsense removed!

 

[holmslaw]

..

 

[Taylortwocities]

That's the problem with the Southern Hemisphere, no sense of reality.

 

[RF Lighting]

If this is a DNO cable you are taking about then as has already been said, stop what ever it is you're trying to do and get the DNO to do it for you.

First of all it is very dangerous for you to work on DNO equipment when you havent got the first clue what you're doing

Second of all it's illegal.

Third of all the DNO do not use SWA cables

Fourth of all the DNO do not install cables as small as 4.0mm² or 6.0mm²

Seriously, just leave it to the people who know what they're doing.

 

[JohnW2]

That's the problem with the Southern Hemisphere, no sense of reality.

Is that where it is? I haven't even bothered to get an atlas out

Kind Regards, John.

 

[dimmer]

This is a block of flats, the service cable entering the flat is SWA, I presume this is OK as it is how the flats were supplied from build. , and have seen SWA used in lots of places to feed from the isolator so don't understand your comments RF


Here is a picture

View media item 42966
The green cable is the earthing conductor to me it looks under sized . But TNS often have a few strands of wire connected to the MET from the lead cable

Thats all this post was about.

If you read what I asked I wanted to know if it is acceptable to have a clamp on this type of cable. and if not hopefully expecting someone to tell me how it should be done.

Is this type of clamp wrong

And is the EC undersized when you do the adiabatic

 

[RF Lighting]

That's not SWA it's pyro.

If you are unsure about earthing arrangements, contact your DNO.

It doesn't matter what we say or think. They are the only people allowed to work on this equipment.

 

[westie101]

YEUCK!!!!!


Bear in mind that the size of that earth cable is nothing to do with the consumer's installation nor does BS7671 apply to it.
As has been said it is the DNO's so talk to them to get it replaced (though they are under no obligation to do so)

Third of all the DNO do not use SWA cables

The word "generally" should be inserted between use & SWA!
Believe me anything is possible!

 

[RF Lighting]

True

I was right on this installation though

 

[dimmer]

Pyro really? it has an outer protective layer like SWA.

Interesting. Thanks

 

[dimmer]

Bear in mind that the size of that earth cable is nothing to do with the consumer's installation nor does BS7671 apply to it.
As has been said it is the DNO's so talk to them to get it replaced (though they are under no obligation to do so)

I do understand that. So in this example with a good Ze, I guess the DNO would not be interested, but is not very good is it.
If I phoned up and said it test ok but looks like sxxx, you would tell me to go away , yes.

I also dont get how the DNO are not required to provide and earth.
Could you explain that one.