Extraneous bonds values

[Guest 004]

Can anybody point to a regulation where 0.05 ohms is the maximum allowed measurement between points.

 

[SPARTYKUS]

This should generate some interesting replies! Good question.

off the top of my head it's mentioned in GN3. I think. Will go and have a look am a bit rusty

 

[HappyHippyDad]

This should generate some interesting replies! Good question.

off the top of my head it's mentioned in GN3. I think. Will go and have a look am a bit rusty

Lucky Nigel didn't ask you that one then Spartykus!

 

[Pete999]

https://www.youtube.com/watch?v=rnvNfI__kYU
Doesn't teel you about which regulation applies but interesting all the same, enjoy

 

[Andy78]

There is no reg that I know of.
It is mentioned in GN3 in the description of continuity testing. I would suggest that GN8 would have more in depth info regarding bonding though.

 

[Geoffsd]

It's not a "maximum allowed measurement between points".

It is a value regarded as negligible impedance and used to verify good connection(s).

 

[driverman]

Can anybody point to a regulation where 0.05 ohms is the maximum allowed measurement between points.

Not max value....but no greater than, I believe is the wording

 

[telectrix]

and what if the bonding conductors are each 10m of 6mm?

 

[Jay Sparks]

This is from GN3

 

[Guest 004]

I had a reading that was 0.5 ohms, and consultant was saying oh that's too high. I was like WTF, are you seriously suggesting that that is not a short circuit? In fact the reading can go much higher and still be a good connection. It's just pure bull.
As nobody can pull any regulation out, just guidance notes, gives me a good argument.

 

[Geoffsd]

I had a reading that was 0.5 ohms,

From where to where?

and consultant was saying oh that's too high. I was like WTF, are you seriously suggesting that that is not a short circuit?

It has nothing to do with short circuit.

In fact the reading can go much higher and still be a good connection.

How do you work that out?

It's just pure bull.
As nobody can pull any regulation out, just guidance notes, gives me a good argument.

It's not a regulation but -

See if you can connect a piece of cable to a pipe and get a reading of more than half an ohm.

 

[Guest 004]

Short circuit is just a figure of speech, as the reading is so low.

The reading was taken from a wall socket earth to the access floor tile.

 

[Guest 004]

Mostly I was getting 0.05 ohms, but in this particular area it was 0.5
Consultant said to run a bond from board to pedal stool. I said I would once all the flooring had been completed. Reply was because the floor was incomplete it can become live. Utter bull****.

 

[Geoffsd]

The reading was taken from a wall socket earth to the access floor tile.

I don't really understand that but -

I think everyone assumed, I did, that you were referring to Main Bonding for which the figure of 0.05 ohms is usually quoted.

Mostly I was getting 0.05 ohms, but in this particular area it was 0.5
Consultant said to run a bond from board to pedal stool.

Again, I don't understand.
Is the floor metal?

I said I would once all the flooring had been completed. Reply was because the floor was incomplete it can become live. Utter bull****.

You are probably right.
Bonding is not applied in case the floor (or anything else) becomes live.

If it is a metal floor and you bond it then the reading will be a lot less than 0.5 ohm.

 

[Guest 004]

The floor is a raised access floor which is metal.
cleaners sockets are on the walls. Hope this makes it more clearer for you.

 

[Geoffsd]

In that case, if you are getting 0.5 ohms between socket CPC and floor then it must be bonded somewhere already.

Is he on about supplementary bonding between socket CPC and floor?

Running a main bond from stool to board would be strange.

 

[shanky887614]

In that case, if you are getting 0.5 ohms between socket CPC and floor then it must be bonded somewhere already.

Is he on about supplementary bonding between socket CPC and floor?

Running a main bond from stool to board would be strange.

its ridiculous, i have come across these floors before.

metal pedestals bolted to floor with metal covered wooden tiles ontop, usually covered with carpet tiles

 

[Guest 004]

Sorry I was nor clear, we was just taking measurements, no bonds were actually in place. The floor will get an earth via floor boxes.
However we was measuring continuity between wall socket cpc, and tile.
All extraneous earth's were measured.
From uni strut to tray work to trunking to ceiling grid to steelwork etc etc etc.
I was just trying to clarify if there was actually an regulation that stated these measurements should be below 0.05 ohms

 

[shanky887614]

Sorry I was nor clear, we was just taking measurements, no bonds were actually in place. The floor will get an earth via floor boxes.
However we was measuring continuity between wall socket cpc, and tile.
All extraneous earth's were measured.
From uni strut to tray work to trunking to ceiling grid to steelwork etc etc etc.
I was just trying to clarify if there was actually an regulation that stated these measurements should be below 0.05 ohms

it would be a lot lower from unistrut etc to it.

it will probably only have 2.5/4mm cpc at most.


there was so many glanded swa and steel in last plantroom the cpc reading was a lot lower than L-N because of parralel paths etc

 

[Guest 004]

Just need an answer to the OP please