which says I can't use the armour of SWA as the only cpc? I'm sure this in not alowed anymore but cant find it in the big red book anywhere
Thanks
Thanks
Where is the reg...
- Thread starter The Dentist
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H
holmslaw
..
You can use the armour as a CPC.
The main reg for you to look at is 543.1.2 which basically allows you to either look at table 54.7 or use the adiabatic equation to calculate the minimum required CSA of armour.
You can determine wether or not a cables SWA automatically complies with table 54.7 by looking at tables such as the ones in the wiki: //www.diynot.com/wiki/electrics:swa-earthing.
Even if they do not comply with table 54.7 they may still be OK with the adiabatic equation, you'll have to number crunch it.
The main reg for you to look at is 543.1.2 which basically allows you to either look at table 54.7 or use the adiabatic equation to calculate the minimum required CSA of armour.
You can determine wether or not a cables SWA automatically complies with table 54.7 by looking at tables such as the ones in the wiki: //www.diynot.com/wiki/electrics:swa-earthing.
Even if they do not comply with table 54.7 they may still be OK with the adiabatic equation, you'll have to number crunch it.
Can't be used? Read 543.2.2
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see 543.2.2 ..V to be precise
Thanks, I'm not going mad afterall, maybe it was a premonition of the 18th Ed
H
holmslaw
..
In virtually all instances where smaller cables are used (up to 25mm), the armour can be used as the cpc.
Although the previously linked table implies otherwise for some sizes, this assumes that the cable will be operating at 90C, which it almost certainly won't be.
Although the previously linked table implies otherwise for some sizes, this assumes that the cable will be operating at 90C, which it almost certainly won't be.
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Seem to remember John Peckham wrote an article on using the armour of SWA cable in one of the IET publications.
He pointed out on the larger cables the steel equivalent size was not big enough.
I think from memory it's around 95mm where one has to be careful. So unlikely to be a DIY problem.
He pointed out on the larger cables the steel equivalent size was not big enough.
I think from memory it's around 95mm where one has to be careful. So unlikely to be a DIY problem.
PVC cables 70C are also on the same wiki page
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