SparkyNinja Webinars

[SparkyChick]

Hi all,

SparkyNinja is running some webinars, you can check them out here:-

SparkyNinja Webinars

sparkyninja.com

I think there will be more added to the list as it sounds like he's got some planned for next week as well.

 

[Pete999]

I'm just putting what the C&G book says but GN3 does also says "When testing the effectiveness of main equipotential bonding conductors, the resistance value between a service pipe or other extraneous-conductive-part and the main earthing terminal should be of the order of 0.05 ohm or less"
Source URL: SparkyNinja Webinars - https://www.electriciansforums.net/threads/sparkyninja-webinars.184880/

but with the Regs and OSG you can measure the length and do the Maths and generally you would be within 0.05

no problems with that statement, what is the query?

 

[pc1966]

I think everyone is happy with "of the order of 0.05 ohm or less" as a reasonable test of stuff bonded with moderate cable lengths.

But not when it is turned in to the belief it must be less than 0.05 ohm!

 

[Pete999]

I think everyone is happy with "of the order of 0.05 ohm or less" as a reasonable test of stuff bonded with moderate cable lengths.

But not when it is turned in to the belief it must be less than 0.05 ohm!

Install a larger main bonding conductor.

 

[Mark Wright]

Install a larger main bonding conductor.

Well I think that was the question raised by one member do you have to have a reading of 0.05 and if you exceed this because of a long run do you need a larger CSA?

But I'm getting a headache so i'm off

 

[davesparks]

It's interesting, as a recently qualified electrician, this value was drilled into students.

Also, when I did 2391 it was seen as the value you cannot exceed.

I just assumed it could never be exceeded in any circumstance

And when you asked the tutors why it had to be 0.05 what did they give as the reason?

Or do you just blindly accept such things without seeking to understand the science behind it?

 

[gazdkw82]

And when you asked the tutors why it had to be 0.05 what did they give as the reason?

Or do you just blindly accept such things without seeking to understand the science behind it?

I donr blindly accept anything. I asked the question.

It's not understanding the science behind the 0.05ohms threshold that is the main question here?

we are trying to determine how this figure is being treated.

I understand the science but I was still wrong in my understanding of what to do when this figure Is not satisfied.

That's what we are trying to accertain

 

[Pete999]

Well I think that was the question raised by one member do you have to have a reading of 0.05 and if you exceed this because of a long run do you need a larger CSA?

But I'm getting a headache so i'm off

Already got one Mate

 

[Mark Wright]

maybe I'm wrong but on his latest video he talks again about taking prospective short circuit current at the end of a circuit and I don't think this is right? it's not the same as an earth fault if a fault starts drawing too much current then the device will trip even if it's a long way away PSCC is only need a the source.

Line and Neutral unlike CPC are the same size conductor.

If it was a long run with then there would be volt drop on both line and neutral, your not going to have a bigger Neutral than your Live are you.

edited sorry pscc

 

[Spoon]

I've only seen some of the Webinars on Youtube.

 

[davesparks]

.
your not going to have a bigger Neutral than your Live are you.

Yes you are if you've have third order harmonics to deal with, the neutral will be oversized to deal with it.