mm2 ampacity restrictions

[Gardner]

Under BS7671, what is the amperage of 1.5mm2, 2.5mm2 and 4mm2 copper conductor restricted to when inside a race way or cable of no more than 3 current carry conductors? Thank you! :smiley2:

 

[Besoeker]

My ex GF had no objection to me calling her a septic.

I note that it's ex GF.

 

[Badged01]

Screwits or Wirenuts, whatever you want to call them were banned by our company during the 2[SUP]nd[/SUP] year of my apprenticeship. I’ll leave it to you to work how long ago that was.

Whilst I agree with you and wouldn't use them myself (they just dont seem right to me for joining cables) there are a lot of "reputable" electrical suppliers out there flogging them quite happily and no-doubt "professional" electricians using them.

Got a big display of them at my local electrical supplier -- and not B&Q before Pete comments!!

 

[Engineer54]

My sweet Southern Belle would be quite offended, horrified even, to be called a Yank.

I'm not too sure i could put up listening to that slow Southern Drawl day in, day out for a lifetime!! lol!!

 

[DPG]

I'm not too sure i could put up listening to that slow Southern Drawl day in, day out for a lifetime!! lol!!

That's a bit offensive isn't it?. Daz

 

[Engineer54]

That's a bit offensive isn't it?. Daz

No, or at least it wasn't meant to be!!

 

[Engineer54]

Whilst I agree with you and wouldn't use them myself (they just dont seem right to me for joining cables) there are a lot of "reputable" electrical suppliers out there flogging them quite happily and no-doubt "professional" electricians using them.

Got a big display of them at my local electrical supplier -- and not B&Q before Pete comments!!

Funny how you never seem to see them out in the field (so to speak) though isn't it!! lol!!

I think they do try to push them, but few ever purchase them

 

[Besoeker]

I'm not too sure i could put up listening to that slow Southern Drawl day in, day out for a lifetime!! lol!!

She has the accent without the drawl.
Customers like it and, to be blunt, we use it to good effect.

 

[Engineer54]

Gardner,

Does your company need to produce/attach any form of installation compliance certificates for these trailers they are exporting into the UK/(EU) that confirms compliance with say BS 7671?? Or do you have an agent or the like, to provide/carry out certificate conformance inspection and testing??

Just wondering, as the power supply and earthing arrangements to these trailers could well be different at every location they are used. (eg Temp mains building supply, Generator supply)

 

[Simonslimline]

In regards to earth loop impedance, this is just to make sure the continuity of the earth conductor is UN-interrupted? My understanding is that the Active and Neutral is shorted to ground at the furthest socket on the circuit and a measurement is taken between the Active and Neutral across to the Earth conductor from that circuit? Active, Neutral and earth are all disconnected from respected terminals at the consumer unit during this test as well as making sure nothing is plugged in.

Guidance Note 3 explains our testing procedures.

 

[Engineer54]

Guidance Note 3 explains our testing procedures.

Errr, i don't think they will have GN.3 readily available in the States!! lol!!

Pointless doing any ELI or live tests on a trailer at the factory anyway... They will only make sense when the trailer is hooked up to the power supply at the location it is to be used....

 

[Simonslimline]

Errr, i don't think they will have GN.3 readily available in the States!! lol!!

Pointless doing any ELI or live tests on a trailer at the factory anyway... They will only make sense when the trailer is hooked up to the power supply at the location it is to be used....

Well he has a PDF of BS7671 from the internet apparently. I don't expect that is readily available either, hence the PDF. I only mentioned it as it might be something he would be interested to read.

 

[Besoeker]

Well he has a PDF of BS7671 from the internet apparently. I don't expect that is readily available either, hence the PDF. I only mentioned it as it might be something he would be interested to read.

Don't think it makes interesting reading......for anyone.
It's just a must have for us sad punters in that field when you need a reference....

 

[Engineer54]

Well he has a PDF of BS7671 from the internet apparently. I don't expect that is readily available either, hence the PDF. I only mentioned it as it might be something he would be interested to read.

Maybe!!....

Unlike the UK and Europe, Testing isn't high on the priority list as far as small and domestic installations are concerned, in the States. There isn't even a section within NFPA 70 (NEC) on the requirements of testing installations, in fact the only measurement i can remember ever seeing in the NEC is the max of 20 or 25 ohms for a single earth rod..... They rely in the States on State employed NEC Electrical inspectors, what sort of tests these guys carry out (if any) i couldn't say.

Very few Master Electricians will own an earth loop impedance tester, GFCI tester, earth leakage clamp tester, etc. Even fewer will own a MFT tester, which i would say in the UK at least, the vast majority of electricians will own.


Typical US journeyman electricians test kit will include ...A good digital multimeter with attachments for various temp probes etc, a basic IR tester, one or more Amp Clamps, volt stick, maybe a two lead volt tester etc... A companies test kit will expand the typical test equipment by providing 3 or 4 point Earth tester, milli ohm high res ohm meter, IR temp or thermal imaging camera, phase rotation tester, etc....

It's a different matter for heavy industry, maintenance departments will often carry an extensive inventory electrical test equipment, often covering both MV and LV installations....

 

[davesparks]

In regards to earth loop impedance, this is just to make sure the continuity of the earth conductor is UN-interrupted? My understanding is that the Active and Neutral is shorted to ground at the furthest socket on the circuit and a measurement is taken between the Active and Neutral across to the Earth conductor from that circuit? Active, Neutral and earth are all disconnected from respected terminals at the consumer unit during this test as well as making sure nothing is plugged in.

Earth fault loop impedance is first predicted by calculation at the design stage and then tested by carrying out a live test known as an earth fault loop impedance test.

The purpose of this is to ensure that there is an earth path of sufficiently low impedance to cause the operation of the OCPD within the required time of an earth fault occurs at the furthest point of the circuit.

I think what you are talking about is the continuity of cpc test carried out as a dead test before live testing starts.

 

[shanky887614]

gairner this will help with the basic's

its a good guide

its the latest version

bs7671 onsite guide