Main bondage

[serpico4321]

Would it not be ok if it satisfied the requirements of R< 50/Ia ? Where Ia is the max current of the protective device? So for 0.3 would be acceptable at 100A

any thoughts?

 

[KAS1]

I ask again where are you getting the 0.3 assuming that's ohms where are you measuring

 

[Geoffsd]

You have to use the current required to operate the 100A fuse 1200 @ 0.4s or 1800A @ 0.1s.
50/ 1200 = 0.04Ω

That's used for supplementary bonding and even there the actual conductor has to be <0.05Ω.

Main bonding conductor conductor must be <0.05Ω.

 

[KAS1]

I think you are getting confused with your Ze measurements, what's the bonding conductor got to do with 100A main fuses?

 

[KAS1]

You must be referring to the Earth Conductor ,,,,,,,,,,,,,,,,,,,

 

[Geoffsd]

My asking where he was testing to and from, as in his domestic situation it seemed as though he was using the 0,05 ohms as a guide for his expected reading of his bonding conductor, I didn't realise he was trying to determine the length of the bonding conductor.

I don't think he is.

In the original question he says

Does main bonding in every circumstance always need to be under 0.05. main bonding in a house where the main water was moved has 10mm cable but resistance of 0.25 ohms!!>>
I don't think the length has anything to do with it apart from the physical impossibilities.

 

[KAS1]

Why is he now quoting 100A fuses lol

- - - Updated - - -

I give up...........

 

[KAS1]

must be getting the wrong end of the stick here lol

 

[Geoffsd]

He's using the formula for whether (supplementary) bonding is required but using the wrong numbers.

See above post.

 

[KAS1]

That's the first time supplementary bonding has been mentioned, as I said where did he get his ohmic value for his main bonding from, where has he measured it to and from............................It's main bonding he has referred to in his question..... did he measure between two pipes, one end of a cable to another, a pipe to a cable I ask again where???

He's using the formula for whether (supplementary) bonding is required but using the wrong numbers.

See above post.