Emergency lighting key switch

[dodge26]

Is there any reg on emergency lighting should be on a key switch in bs7671, I know of it coming up in bs5266.

 

[telectrix]

not that i know of. the keyswitch method of interrupting the feed to the em's is basically so you can test them without interrupting the feed to the "normal" lights. a matter of safety and convenience. nobody likes to work in the dark if possible.

 

[dodge26]

So could the isolation of an mcb, be a suitable test method as highlighted in bs5266?

 

[telectrix]

problem there is that either the MCB will switch off the "normal" lights, or, if you feed the permanent em line from a different MCB, you would have 2 line feeds into fittings, which is not good.

a different story if the em's are independent of the "normal" lights. but that would bring up the problem of the em's not activating when the lighting failed.

so, we're back to keyswitches being the best way to meet all requirements and regulations.

 

[dodge26]

Regrdless of the darkness issue, on the 3 hour emg test, on the tick sheet there is the question, does the system have a suitable test facility. MCB suitable or not.

 

[telectrix]

all boils down to whether or not it is acceptable to switch off the lights for 3 hours. i would not call that a suitable test facility. a keyswitch or even an unswitched spur ( supplying the permanent line) would do.

 

[mogga]

some commercials have a LMO switch on contactors so Iv seen feed from mcb to 2 contactors no1 LMO switching no2 Emlighting bank of contactors from different phases

 

[dodge26]

Are we saying there is no requirement for a key switch, if they are happy sitting in darkness for 3 hours?

 

[telectrix]

till someone falls over the cat, breaks a bone or 2, then sues you

 

[dodge26]

Love this forum, you never seem to get a straight answer, bit like the regs....

 

[Spudnik]

There is no real answer, although the key switch method mentioned is a valid way of providing suitable testing facilities for em's.

You dont have to use them, but as you are the installer, any issues arising from them not being fitted is down to you.

What answer were you hoping for?

 

[netblindpaul]

Look at your state law duties as a designer under CDM then you will have your answer I think.

 

[Engineer54]

Love this forum, you never seem to get a straight answer, bit like the regs....

How many straight answers do you need then, before the penny drops??

If your looking for some sort of get out clause, there isn't one. The key switch method is generally accepted as the way to isolate the EM/lighting side of things. You can use other methods as others here have stated, such as unswitched FCU and the like, but the key switch method best meets all the requirements for testing and isolation.... Yep, it's that simple!!

 

[Andy 7671]

P4 is it...? cant remember.

Data cable that monitors state of battery via computer interface. No need for keyswitch

I asked the commissioning engineer if there was any need for a visual check when testing EMs, "Nope" he replied just trust computer.

I didnt like that answer.

 

[Tosh]

an m.c.b is suitable yes.. and depending on how its wired all lights on that circuit would go out anyway.. an m.c.b can also be used as a functional switch too..

 

[i=p/u]

depends on the actual building and its use aswell, im only little fish in big pond and any ive tested 2 restaurants, the key switch didnt work so i knocked off mcbs. but because the chinnese start early i was there at 9am as soon as doors open as this was appropiate time for full duration test.. so no you dont need it but if you bigger building maybe you do and if you in biger important building you might need the computer controlled version...

 

[ezzzekiel]

Do people tend to run two lives back from switch and continue the em light feed through whole circuit then

 

[i=p/u]

the ones i tested were just tapped off lighting circuits, non maintained and maintained ones near doors and stuff just had perm feed,

the other ones i tested in block of flats were maintained and running off a sensor when it gets dark....

 

[ezzzekiel]

Just figured if fed through single key switch to all lights then no reason not to fit one just one extra core run through

 

[mogga]

there are Em lights with built in test buttons ones with remote control testing buttons i
the answer to the question is realy "what is suitable and most appropriate for the job Im doing?"

 

[Engineer54]

P4 is it...? cant remember.

Data cable that monitors state of battery via computer interface. No need for keyswitch

I asked the commissioning engineer if there was any need for a visual check when testing EMs, "Nope" he replied just trust computer.

I didnt like that answer.

The guy is talking out of his arse!! So this numpty doesn't bother to give the EM L's a duration test in his commissioning procedures, ...I wonder what he puts down on his testing commissioning sheets, Battery voltage?? Is this guy talking about a central battery supplies for the EM L's?? I hope so, taking a point to every EML in a building, will sure eat up monitoring points ...lol!! BMS systems are very, very useful tools, but they don't and can't substitute for testing procedures!!

 

[i=p/u]

but they do, cause ive read it somewhere the new stuff tests auomatical or is monitored in a way that it tells you when a fault.... its their selling point... maybe more to it than the selling point as this is when they highlight the good points... im nearly sure they said you can link upto 15000 points per system

 

[Deleted member 26818]

Is there any reg on emergency lighting should be on a key switch in bs7671, I know of it coming up in bs5266.

No there isn't, and I'm not aware that such a requirement has been proposed for BS5266.
The use of an MCB for testing is quite acceptable, however key switches are usefull if you just want to test a part of the system.
As for the users being in the dark, one of the reasons it is a good idea to switch off the normal lights when testing the EM lights, is to ascertain whether the EM lights are working, and providing sufficient light levels.
As such anyone tripping over cats should get glasses, or get a job in a Dog's home.

 

[Engineer54]

but they do, cause ive read it somewhere the new stuff tests auomatical or is monitored in a way that it tells you when a fault.... its their selling point... maybe more to it than the selling point as this is when they highlight the good points... im nearly sure they said you can link upto 15000 points per system

All BMS systems do exactly that, but they do not substitute for periodic testing full stop!!
They monitor, control, they give alarms, and information, record, access data, etc... They are sophisticated bits of kit that have numerous optional extras you can add, many of which are basically useless, but look good on the screen.

I don't think i've worked on a BMS system with just 15K points, 25 to 30K is roughly the norm on any decent sized project, but can be substantially more. The bigger the system the more important it is to have a top notch operating system that works in real time, with minimum delay times for registering alarms and faults.

 

[Andy 7671]

The guy is talking out of his arse!! So this numpty doesn't bother to give the EM L's a duration test in his commissioning procedures, ...I wonder what he puts down on his testing commissioning sheets, Battery voltage?? Is this guy talking about a central battery supplies for the EM L's?? I hope so, taking a point to every EML in a building, will sure eat up monitoring points ...lol!! BMS systems are very, very useful tools, but they don't and can't substitute for testing procedures!!

Sorry, just to be clear, I asked him "When there is a key switch, this is activated during a test and the engineer or maintenance man WALKS ROUND AND VISUALLY OBSERVES emergency lighting, does he still need to do this...?"

His reply was no, the device monitors it.

I guess he was taking a point to every EM, two cables orange and white.

 

[i=p/u]

your the man, was thinking if i know this well ur man e54 does..

All BMS systems do exactly that, but they do not substitute for periodic testing full stop!!
They monitor, control, they give alarms, and information, record, access data, etc... They are sophisticated bits of kit that have numerous optional extras you can add, many of which are basically useless, but look good on the screen.

I don't think i've worked on a BMS system with just 15K points, 25 to 30K is roughly the norm on any decent sized project, but can be substantially more. The bigger the system the more important it is to have a top notch operating system that works in real time, with minimum delay times for registering alarms and faults.

 

[netblindpaul]

Sorry, just to be clear, I asked him "When there is a key switch, this is activated during a test and the engineer or maintenance man WALKS ROUND AND VISUALLY OBSERVES emergency lighting, does he still need to do this...?"

His reply was no, the device monitors it.

I guess he was taking a point to every EM, two cables orange and white.

Thing is the BMS can monitor the supply, the charge & the battery voltage if it can disconnect the charge, it can even monitor the voltage to the tube and both in and out, again if it can disconnect the supply thus so proving the tube has power, but now we are up to 5 points per NM fitting, along with a mechanism to disconnect the mains supply.
What it can't do is walk around and check the light levels from the tube, which IIRC is still required under the BS, that is unless you put loads of light sensors around the building to check the light levels again one per monitoring point, and how many light level monitoring points would you need to prove each EM fitting is providing sufficient illumination...

 

[i=p/u]

so they havent took over emergency light fully, we still nee a man on the ground, yesssssssssssssssssssssssssss!

 

[dodge26]

How many straight answers do you need then, before the penny drops??

If your looking for some sort of get out clause, there isn't one. The key switch method is generally accepted as the way to isolate the EM/lighting side of things. You can use other methods as others here have stated, such as unswitched FCU and the like, but the key switch method best meets all the requirements for testing and isolation.... Yep, it's that simple!!

Ooooh strong comment, if you actually read the whole thread you get a straight answer in no there isn't a requirement according to bs5266 to fit a key switch, later in the thread which was a direct answer I was after. Nothing needed on tripping on cats and testing in the dark rubbish.