Single Point Of Isolation?

[bunny8669]

Been having a discussion with a colleague about installations with multiple fuseboads.

Basically we disagree, if an installation has multiple boards fed from 1 intake or busbar chamber does it require a single point of isolation for the whole installation? A switch fuse controlling the busbar for example

 

[Andy™]

each installation must have 1 point of isolation... but you can have as many installations as you like...

but there would usually be some kind of isolation to a busbar chamber

 

[bunny8669]

Would a main fuse be classed as a point of isolation? In an emergency you have to take a cover off and remove 3 individual fuses (if it's a 3 phase supply

 

[Evans Electric]

I think it was agreed that  any industrial or commercial building should have one Main Switch to isolate the whole installation .  However a large , sprawling complex would have to have more than one  .

I'm fairly sure this did NOT apply to domestic work , hence those places with 3 boards , a shower unit , a garage unit , off peak heating  etc 

Would a main fuse be classed as a point of isolation? In an emergency you have to take a cover off and remove 3 individual fuses (if it's a 3 phase supply

In an emergency it would need to be a switch  or sw/fuse TBH .   You would'nt want untrained persons removing covers & pulling  fuses on a TPN supply.

 

[Blue Duck]

Firemans switch?

 

[NozSpark]

I showed a job on my AC assessment that I'd fed a sub DB via a switch fuse which was just connected via henly blocks..... This sub DB was in a new extension and supplied all the final circuits within it. The other DB supplied all the final circuits within the main part of the house

 

[steptoe]

I showed a job on my AC assessment that I'd fed a sub DB via a switch fuse which was just connected via henly blocks..... This sub DB was in a new extension and supplied all the final circuits within it. The other DB supplied all the final circuits within the main part of the house

but niccy dont work to BS7671,

they use NICEICs amended version of BS7671 with their owns bits put in and others taken out,,,   :|

 

[NozSpark]

He did comment on it but after a bit of discussion we decided that it could be seen as a separate installation... There were no rooms with mixed "origins" (as were) and there was a clear demarcation between the house and extension..

The main problem with that job was that my client had replaced some wall lights and had insulation exposed outside of the fitting,,,, also a conservatory had been built and they had tapped into my socket circuit for power and lights - cables were definitely run outside of zones

I still passed

 

[Adrian]

how about an off peak board and normal board most installs come straight from meter so no single point of isolation there.  

 

[kerching]

how about an off peak board and normal board most installs come straight from meter so no single point of isolation there.

On the better jobs I have seen an REC4 fitted...but not often