How to conduct safe isolation on this main switch ?

[Rob678]

Hi all, if I cannot access the line side of a crabtree 100A DP main switch. Would someone enlighten me how to conduct safe isolation on this installation. Would the main fuse need to be removed ? Thankyou.

 

[rich7469]

https://www.electricalsafetyfirst.org.uk/media/blak1wkt/best-practice-guide-2-issue-4.pdf

 

[westward10]

What is it you are wanting to do?

 

[Rob678]

What is it you are wanting to do?

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

 

[westward10]

Safe isolation to replace it, work on it?

 

[Rob678]

Safe isolation to replace it, work on it?

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.

 

[Rob678]

What is it you are wanting to do?

What is it you are wanting to do?

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 ?

 

[snowhead]

Ah, so your enquiry relates soley to the pictured Isolator, with missing terminal to test at.
What make is it?

 

[westward10]

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.

 

[Rob678]

Ah, so your enquiry relates soley to the pictured Isolator, with missing terminal to test at.
What make is it?

View attachment 111110

Yes 100%, the product is a Crabtree star breaker 100A DP main switch disconnector.