Am I being harsh?

[nunthe wiser]

I've seen individual fittings with a keys witch alongside, but mostly separate feed from board to bank of contractors on a board extension controlled from key switch at panel. Testing lights by isolating at Mcb's is frowned upon now.

 

[Deleted member 26818]

My understanding is also that BS5266 requires the test switch to only operate the emergency lighting, and not switch off the normal lighting.
Unfortunately doing such is not satisfactory for a couple of reasons.
With many maintained lights, there will be no indication that the em light is operating other than the charging indicator lamp will go out.
Another problem is that there is no indication whether lux levels are sufficient.
Lux levels can be altered by alterations to the fabric of the building, deterioration of lamps, accumulation of dirt and grime or even a change in decor.
To my mind it is ludicrous to require a testing system which will not even indicate that the em lights are working, or allow an assessment of lux levels.

 

[YoungBart]

I must admit I always thought it was in the Regs for emergency Keyswitches to be marked up as such, But I've had a quick scan through and cant find it so I assume I am wrong and that it's just good practice.
I've wired emergency lighting systems In both ways stated, And IMO it makes more sense for an emergency keyswitch to override the normal lighting circuit as well, I can however also see that from a safety point of view It's better just to test the emergency circuit. I believe I asked the same question on another post, and was told That emergency switches should only isolate the emergency circuit as Risteard has said.

 

[Risteard]

Unfortunately doing such is not satisfactory for a couple of reasons.
With many maintained lights, there will be no indication that the em light is operating other than the charging indicator lamp will go out.
Another problem is that there is no indication whether lux levels are sufficient.
Lux levels can be altered by alterations to the fabric of the building, deterioration of lamps, accumulation of dirt and grime or even a change in decor.
To my mind it is ludicrous to require a testing system which will not even indicate that the em lights are working, or allow an assessment of lux levels.

To be fair if the charge indicator ceases to illuminate (but illuminates when the supply is restored) then it would seem reasonable to assume that an emergency luminaire had been running off the battery during test.

As for lux levels etc. these do not need to be determined during the monthly test etc. If you wanted to determine them at another time this could easily be achieved by isolating all of the lighting in the area when it is dark (and when the building is not in use of course). That doesn't mean that the test switch isn't suitable for ensuring the emergency luminaires are operating on failure of the supply.

It should also be remembered if running a full duration test that the batteries will be discharged and the premises should not be reoccupied until they have fully recharged (which could take 24 hours or so).

 

[mattg4321]

The main problem with wiring as Risteard says is the 'trained' person forgets to turn the keyswitch back on. Easily done with a maintained fitting as the only giveaway is there is no green/red indicator light. An even bigger problem if the lights are designed to be on 24/7 or on a PIR etc so they are switched on at the time of the test.

Seen it happen a few times. On one occasion it caused problems when the keyswitch had been left off by accident. The battery discharged, had a power cut and no emergency lighting.

IMO whatever the regs say, both ways of doing it have their merits/flaws and sometimes one might be more suitable than the other.

 

[Risteard]

IMO whatever the regs say, both ways of doing it have their merits/flaws and sometimes one might be more suitable than the other.

I really can't agree. An emergency lighting installation must comply with BS 5266 as well as BS 7671. It would be pretty foolish to claim that non-compliance with the emergency lighting Code of Practice was reasonable.

 

[davesparks]

IMO whatever the regs say, both ways of doing it have their merits/flaws and sometimes one might be more suitable than the other.

Except we aren't dealing with bs7671 here and it's wishy washy non statutory status. The emergency lighting code of practice is specially designed to ensure compliance with the legal requirements.

 

[Deleted member 26818]

To be fair if the charge indicator ceases to illuminate (but illuminates when the supply is restored) then it would seem reasonable to assume that an emergency luminaire had been running off the battery during test.

As for lux levels etc. these do not need to be determined during the monthly test etc. If you wanted to determine them at another time this could easily be achieved by isolating all of the lighting in the area when it is dark (and when the building is not in use of course). That doesn't mean that the test switch isn't suitable for ensuring the emergency luminaires are operating on failure of the supply.

It should also be remembered if running a full duration test that the batteries will be discharged and the premises should not be reoccupied until they have fully recharged (which could take 24 hours or so).

Sorry, didn't realise that the sole purpose of the test was to check the indicator lights.
I would have thought a test to check that the em lights function as designed would be a good idea.
I guess it all depends on the reason why the em lights have been installed?
If they have been installed just to pander to some safety code, then checking the indicator lamps function may be enough.
If however they have been installed to provide adequate lighting in the event of a failure of the normal lighting, then a test to ensure that they do provide the adequate lighting required would to my mind be sensible.

 

[mattg4321]

Dave and Risteard, I don't disagree that your way is the 'official' way of doing it (and the way I would begrudgingly wire it), I just don't think it's the best way.

 

[Risteard]

Sorry, didn't realise that the sole purpose of the test was to check the indicator lights.
I would have thought a test to check that the em lights function as designed would be a good idea.

The point is if they illuminate (if non-maintained) or remain illuminated (if maintained) after killing the supply (as verified with the charge indicator) then you do know that they are operating from the battery. The monthly test is only a simple walk-round to verify that the lamps are illuminating and that they have returned to charging mode afterwards. So the keyswitch is ideal for it.