Proving dead & safe iso on Economy 7

[NickD]

Interested to hear people's thoughts on best practice for proving dead and achieving safe isolation on an Economy 7 board - the problem being, (unless you work 0000-0700 GMT :wink5 the Economy 7 supply is unenergised. So 'proving' your means of isolation achieves dead actually proves nothing, because even if you had failed to isolate it'd be dead anyway - the supply is unenergised. And the energisation of the Economy 7 is outside your control, and for life criticality it's not good enough to assume it can only ever come live during the wee small hours - accidents and errors happen.

In increasing order of derangement, my thoughts currently include
- pulling the cutout fuse (would you do it if you were being assessed though?)
- carefully (no touchee copper) removing the Economy 7 tails from the main switch and isolating them in connector block
- insulation testing supply-to-load on both the L and N side of the main switch after turning off, to prove the switch open

(tin hat on, finds parapet)

 

[Lee Marshall]

just go during the day lol

 

[Octopus]

I was testing an E7 system a few months ago and then at 3pm, just as I was finishing, the timer switched it on. Thankfully I didn't have my fingers in the board at the time. lol

 

[BrianDB9]

Get a contractor switch fitted.

Prove GS38 Testers on known live source and check circuit is dead is about as much as i can think of - HSE wouldnt take kindly to any risk.
They've even stopped us doing live tests only Zs = Ze +r1+r2 now

 

[Lee Marshall]

I was testing an E7 system a few months ago and then at 3pm, just as I was finishing, the timer switched it on. Thankfully I didn't have my fingers in the board at the time. lol

did the heatwise kick in for an hour? lol

 

[NickD]

just go during the day lol

I am. That's the problem dude!

 

[NickD]

Prove GS38 Testers on known live source and check circuit is dead is about as much as i can think of

But that's my point. This proves naaaaathing when the supply is dead anyway, but can be energised outside of your control. Same problem must pop up for PV I guess when it's dark, very cloudy or Wales.

 

[lauriehurman]

I agree with Murdoch
Watch out for the "afternoon boost".
Laurie

 

[Guest55]

wtf is this sh**e ?
why cant you just turn off the main sw ?
it wont matter if the teleswitch is energised or not.
and as for pulling out tails and sticking in connector blocks ?? get a grip or just pack in electricals before you have an accident..

 

[Octopus]

I agree with Murdoch
Watch out for the "afternoon boost".
Laurie

Wasn't an afternoon boost, the clock was very wrong.