Select (Scottish) Certification Scheme Question on volt drop from 2391

[Mark Wright]

No,like I say it is not a requirement to measure it on a EICR

Don't you still have to fill in a Generic Schedule of test results?
Even though you have agreed limitations with the client etc.

 

[Ian1981]

Don't you still have to fill in a Generic Schedule of test results?
Even though you have confirmed limitations with the client etc.

Yes you fill in test results, as far as ADS is concerned you need the measured Zs for the circuits.
It does not necessarily mean that each circuits cpc is continuous as you may pick up a cpc by parallel paths but there’s no requirement for a circuit to have its own cpc (take trunking systems , conduit where the containment is the cpc for multiple circuits. )
We are primarily interested that the circuits ocpd will operate in under the required times.

 

[Mark Wright]

sorry Im getting bit confused here wires crossed I think
You don't need a reading of R1+R2 for periodic inspection if you agreed that limitation with you client but there is a Schedule of test results ?

 

[Ian1981]

sorry Im getting bit confused here wires crossed I think
You don't need a reading of R1+R2 for periodic inspection if you agreed that limitation with you client but there is a Schedule of test results ?

It’s not a limitation, it’s not required full stop for a EICR but it’s not precluded either.
Record it if you wish and add it to the Ze if you do not want to directly measure zs.
It’s pointless in certain installations tho and unachievable.

 

[AJshep]

But the question has no information to state the cables will be running at 70C, nor the information (if any) to calculate what temperature it might be operating at.

What if it were XLPE SWA at 90C instead?

What if a long run of 16mm that would barely show any rise?

The examiners deserves a boll0cking for that.

C&G do this alot especially in multiply choice papers, although the wording they use is generally "maximum volt drop" I believe they just do it to check the candidates knows how to apply basic correction values, as they always give both answers.

Another one they like to check is that the candidates are applying 80% to the max Zs values in the BBB.

 

[Mark Wright]

Chris Kitcher does use 1.2 in his video and gives an explanation so yeah your right

View: https://m.youtube.com/watch?v=f1NNHgxHiBw

[automerge]1596759536[/automerge]
so at a guess the mV/A/M values from OSG etc are actually at Max working temp already i.e 70°C

 

[Stalag71]

Chris Kitcher does use 1.2 in his video and gives an explanation so yeah your right

View: https://m.youtube.com/watch?v=f1NNHgxHiBw

[automerge]1596759536[/automerge]
so at a guess the mV/A/M values from OSG etc are actually at Max working temp already i.e 70°C

It's my understanding that the values in the OSG are adjusted for temp which accounts for the difference you'll find in tables for max Zs etc....because the OSG is your go to while 'in the field' and BS7671 would be your go to when carrying out 'design'.