Emergency Lighting Tests - should normal lights go off?

[Slowbutsure]

Hi There

I work on a large Government site with 500+ emergency lights, both maintained and non-maintained. Some of the emergency lighting circuits are wired so that upon carrying out a key switch test the normal lighting goes off.

But there are some emergency lights where the normal lights stay on during a key switch test. So I am trying to establish if the normal lights should go off during a key switch test or not. The 17th Ed. wiring Regs do not say much so I went and bought the IET guide to Emergency lighting but this also did not clarify if normal lighting should stay on during a key switch test!

Can anyone clarify?

 

[Richard Burns]

I believe the approach now is that normal lighting should not go off when the emergency lighting is being tested as this could cause danger if the testing is being done during working hours.
However this was not always the case and often EM lights were wired so that the whole lighting circuit was powered down on operating the test switch. (and quite often I have seen EM lighting where the lighting MCB is used as the test switch! simple but not sensible)

If you have an installation where the normal lighting goes out then you have to take this into consideration when testing.

 

[Leyland30]

As your already aware - The key switch is provided to put the emergency luminaries into emergency mode for testing purposes. It might be preferential to have the non-emergency luminaries remain on during this test but it isn't a requirement. Bs 7671 won't be particularly helpful to you, try bs 5266-1 2016. 5266-1 also has guidance on testing procedures which may benefit you. Thanks

 

[Slowbutsure]

I believe the approach now is that normal lighting should not go off when the emergency lighting is being tested as this could cause danger if the testing is being done during working hours.
However this was not always the case and often EM lights were wired so that the whole lighting circuit was powered down on operating the test switch. (and quite often I have seen EM lighting where the lighting MCB is used as the test switch! simple but not sensible)

If you have an installation where the normal lighting goes out then you have to take this into consideration when testing.

Thanks Richard - I will check the installations, maybe the difference is between occupied and non-occupied areas.

 

[Leyland30]

Creating a dangerous environment due to the activation of a test is not advisable. A review of the buildings o and m manual should reveal when it was originally designed to be tested i.e. Out of hours, this might also give the installation time to recharge before reoccupation. If a full duration test is allowable during occupation you should be considering whether there is sufficent energy remaining in batteries to facilitate a successful evacuation.

 

[westward10]

BS5266 will provide no guidance and never has on this, only that some means of test facility is provided. Some believe that a test facility interrupting the general lighting provides a realistic scenario for the effectiveness of the emergency lighting, this is nonsense as the test facility is there to test the operation of the fittings and no more. In some cases loss of general lighting is not too much of a problem but it can also pose a real risk to persons in an occupied premises. The use of a mcb for the testing is not acceptable for compliance with BS5266. I suspect that this along with a vast majority of emergency lighting installations in this country has been installed and tested by persons who do not have copies of the relevant BS5266 standards and hence have no understanding of the systems.

 

[Risteard]

That is not true. BS 5266-1:2011 explicitly states that the test facility MUST NOT interrupt the normal lighting.

BS5266 will provide no guidance and never has on this, only that some means of test facility is provided. Some believe that a test facility interrupting the general lighting provides a realistic scenario for the effectiveness of the emergency lighting, this is nonsense as the test facility is there to test the operation of the fittings and no more. In some cases loss of general lighting is not too much of a problem but it can also pose a real risk to persons in an occupied premises. The use of a mcb for the testing is not acceptable for compliance with BS5266. I suspect that this along with a vast majority of emergency lighting installations in this country has been installed and tested by persons who do not have copies of the relevant BS5266 standards and hence have no understanding of the systems.

 

[westward10]

That is not true. BS 5266-1:2011 explicitly states that the test facility MUST NOT interrupt the normal lighting.

Well I stand corrected, I will always note this down anyway.

 

[Risteard]

"8.3.3 Test facility
"Each emergency lighting system should have suitable means for simulating
failure of the normal supply for test purposes (i.e. without interruption of the
normal supply).
"NOTE An automatic test system for battery powered emergency lighting is specified in BS EN 62034."

It is worth noting that BS 5266-1:2016 was recently published which has altered the wording displayed in BS 5266-1:2011 (above). So it may not be a requirement any longer although I will have to have a proper read through the new Standard to verify that.

 

[westward10]

Now you have worded it this is familiar, got new copy somewhere but I wouldn't have thought it has changed.

 

[Risteard]

Now you have worded it this is familiar, got new copy somewhere but I wouldn't have thought it has changed.

The wording definitely has changed, but I don't have my copy of BS 5266-1:2016 on me at the minute so can't post the new wording.

 

[snowhead]

2016 edition 8.3.3.

Now Includes the line,
The test device should not interrupt power to any other electrical equipment
that could cause a hazard.

 

[Deleted member 26818]

I also understand that illuminated exit signs in public buildings are supposed to be lit when occupied.

 

[westward10]

I also understand that illuminated exit signs in public buildings are supposed to be lit when occupied.

It is recommended and if maintained they should be illuminated at material times anyway.

 

[Deleted member 26818]

It used to be only in licensed premises such as cinemas, clubs, pubs, etc.
Anywhere that it would be expected to be dark during normal operation.
Now I understand that it is also in schools, hospitals, courts, etc.
Places where it would not be expected to be dark during normal operation.