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- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
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- Jul 15, 2016
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- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
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Conduct safe isolation of the consumer unit. However once I have proved my my voltage meter works. How would I be able to conduct L-N, and L-E on the consumer side of the main switch ? The face of the screw is covered by plastic
- Jul 15, 2016
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Neither in this instance. Just purely interest. So far in my apprenticeship we have always been able to conduct the safe Isolation tests on L-E L-N and N-E. As I can use my voltage detectors on the non-supply side of the main switch. I don’t understand how I would be able to conduct safe isolation on this main switch to ensure the board is safe to work on if I was to remove an mcb or RCBO ? I understand if I needed to remove the main switch DNO would need to be contacted as that involves work on the supply side.
For example in one photo I can get a probe onto the Line side in the other photo I can’t. On the one I can’t how would I conduct SI ?
Attachments
Ah, so your enquiry relates soley to the pictured Isolator, with missing terminal to test at.
What make is it?
What make is it?
- Jul 15, 2016
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- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
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That is an isolator for a Crabtree Starbreaker CU. The only way you can prove the outgoing side is dead is at the protective device terminal as the live terminal from the isolator plugs onto a busbar.
Yes 100%, the product is a Crabtree star breaker 100A DP main switch disconnector.
D
davesparks
Presumably a crabtree starbreaker CU where everything plugs into the shrouded busbar?
I think you would have to use the outgoing terminals of the protective device(s)
I think you would have to use the outgoing terminals of the protective device(s)
Yes Dave that is correct. That’s the only solution in my head I could come up with. But I thought surely there must be another route ? Have looked for many sources online but couldn’t find an answer.
D
davesparks
Why would you need another way?
This is a genuine question as there is an argument you could make as to a, very unlikely, scenario which could make this method unsuitable.
I suppose you wouldn’t. I meant that question more in the sense I felt like I’d be doing something wrong as I have always completed SI from the Main switch in this scenario
D
davesparks
OK, so the very unlikely scenario is the MCB going faulty at the same time as you open the main switch, this could give a false result on your safe isolation test.
This is an incredibly unlikely thing to happen and you can mitigate it by testing at multiple protective devices just to be sure.
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