Connecting load to a live FSU - Legal?

Andy Ellis · Apr 22, 2016

I work with fire alarm panels and have recently come across a situation where my customer could not isolate the FSU recently installed for me as the FSU was fed from a breaker than would have caused major disruption if knocked off.

Now when I did my City&guilds 2330 & BS7671 they taught me no live working at all, and only very limmited live testing.

My qustion is, is it reasonable and fairly normal to connect the load to a FSU whilst the supply side is live?

I'm fully aware of the dangers etc, and Im more than competant.. Im more worried about one of the cores breaking and earthing on backbox knocking rcd's galore off.

Im trying to find out for my employer to be quite honest, not in a bad way, we just guinennely want to know if this is acceptable? or if the EWR would cut our nuts off. Must my employer insist we must be able to isolate all FSU's? (my personal thought).

Andy78 · Apr 22, 2016

The Electricity at work act has very clear rules about live working and is a statutory requirement.
http://www.hse.gov.uk/pubns/priced/hsr25.pdf

Safe isolation should be carried out to ensure you are minimising risk in accordance with the EAWR
http://www.----------------------------/mediafile/100117573/Best-Practice-Guide-2.pdf

What is a supply for a fire alarm doing on a breaker that would cause disruption if isolated ? Surely it should be on a dedicated circuit ?

Risteard · Apr 22, 2016

As stated, it would be hard to see how there could be any argument that working on it live would be anything other than illegal.

LankyWill · Apr 22, 2016

not really an issue, if you pop the fuse from the fcu. It shouldn't arc and the neutral never does. Not saying its the right practice, but hardly a death defying incident. I mean sometimes its just not practical to power down an install to connect simple stuff. If you dont feel comfortable, Dont do it. In large commercial and industrial environments when there is a fault its pretty much do what it takes without disrupting anything. Sickening really.

Pete999 · Apr 23, 2016

Andy Ellis said:
I work with fire alarm panels and have recently come across a situation where my customer could not isolate the FSU recently installed for me as the FSU was fed from a breaker than would have caused major disruption if knocked off.

Now when I did my City&guilds 2330 & BS7671 they taught me no live working at all, and only very limmited live testing.

My qustion is, is it reasonable and fairly normal to connect the load to a FSU whilst the supply side is live?

I'm fully aware of the dangers etc, and Im more than competant.. Im more worried about one of the cores breaking and earthing on backbox knocking rcd's galore off.

Im trying to find out for my employer to be quite honest, not in a bad way, we just guinennely want to know if this is acceptable? or if the EWR would cut our nuts off. Must my employer insist we must be able to isolate all FSU's? (my personal thought).

Andy78 has said it all.

Andy Ellis · Apr 23, 2016

Its not the actual alarm panel itself, its a supply for an 'accessory' that needs 230v, so usually fed from a ring which in say a school might have tons of other sockets currently being used.

I have looked at the eawr but since this is not actually a 'live conductor', I was struggling to apply it?

snowhead · Apr 23, 2016

Andy Ellis said:
I have looked at the eawr but since this is not actually a 'live conductor', I was struggling to apply it?

Reg 14;
No person shall be engaged in any work activity on or so near any live conductor (other than one suitably covered with insulating material so as to prevent danger ) that danger may arise unless,