Emergency lighting help

[Jon West]

Good afternoon,

yesterday we had a power cut in our care home, 2 emergency lights did not kick in. They kick in on the key flick test which i do every month but they do not kick in when i switch off the MCB in the consumer unit. We have just had new batteries put in and they are fully charged. The green led is on when the power is on. We do have a contract for maintenance with Lowe and Oliver but as maintenance manager if i can fix it it will save the call out fee. Any ideas why they would work on a flick test but not a full power cut?

 

[davesparks]

The lights illuminate when the test switch is operated.
The lights do not illuminate when power to the entire installation is lost, ie. a power cut.

That is not likely to be caused by the lights being fed from a different circuit.

My guess would be that the test switch is incorrectly wired so that it is connected to the switched live terminal thus switching the light on rather than simulating a power failure.
If this is the case then it probably doesn't have an unswitched supply at all and so the battery hasn't been charged.

 

[Zdb]

the light kicks in on EL flick test, but not when the mcb is switched off.

If they're non maintained and work on the flick test then they will work in a power cut.

You must be switching the wrong MCB off.

 

[davesparks]

If they're non maintained and work on the flick test then they will work in a power cut.

You must be switching the wrong MCB off.

He has stated that they did not work in a power cut.

Don't assume that the test switch has been wired correctly,

 

[Zdb]

But he also stated that the green indicators are normally on, and switch off when in test.

 

[davesparks]

But he also stated that the green indicators are normally on, and switch off when in test.

Which could just be the lamp obscuring the LED

 

[westward10]

Depending on where the board is they may illuminate for a short period then have failed by the time he gets there. He may only be flicking the test facility quickly but need more info and he seems to have gone.

 

[davesparks]

Depending on where the board is they may illuminate for a short period then have failed by the time he gets there. He may only be flicking the test facility quickly but need more info and he seems to have gone.

It's seems unlikely if they have new batteries, but of course is not impossible.

 

[Lucien Nunes]

The OP doesn't say explicitly that the charge indicator goes off when the test switch is operated, only that it did when the supply was pulled. The only consistent explanation seems to be Davesparks'...

 

[westward10]

It's seems unlikely if they have new batteries, but of course is not impossible.

May have replaced batteries due to previous failure when in fact that wasn't the issue, like you say maybe no permanent supply or the fiitings have duff charging parts.

 

[Jon West]

Have they ever worked properly

If they're non maintained and work on the flick test then they will work in a power cut.

You must be switching the wrong MCB off.

100 percent the correct mcb as all the lights in that corridor go off when the power is cut.

 

[Jon West]

Depending on where the board is they may illuminate for a short period then have failed by the time he gets there. He may only be flicking the test facility quickly but need more info and he seems to have gone.

Nope, i can see the lights from the consumer unit and watch the lights when i switch them off.

 

[Lucien Nunes]

Hmm. If the green LEDS stay on when the test switch is operated, the wiring is wrong as per Davesparks' suggestion but the fact the LED is on should indicate reliably that the battery is on charge, not merely that the PL is live. So although the test switch would not test the fitting in the intended manner, if the battery is good then the fitting should still function during power loss. If the green LEDs go off when the test switch is operated, then there's no evidence of a wiring error and again the fitting should still work.

I think we've gone as far as we can go with the evidence available and investigation with test equipment is now needed to make any useful progres...

 

[Jon West]

Depending on where the board is they may illuminate for a short period then have failed by the time he gets there. He may only be flicking the test facility quickly but need more info and he seems to have gone.

Nope, i can see the lights from the consumer unit and watch the lights when i switch them off.

Which could just be the lamp obscuring the LED

The green led is illuminated and goes off when flick tested and mcb switched off.

 

[westward10]

So test facility operates them all but the mcb does not even though all the charge leds extinguish when the mcb is off.

 

[Jon West]

Hmm. If the green LEDS stay on when the test switch is operated, the wiring is wrong as per Davesparks' suggestion but the fact the LED is on should indicate reliably that the battery is on charge, not merely that the PL is live. So although the test switch would not test the fitting in the intended manner, if the battery is good then the fitting should still function during power loss. If the green LEDs go off when the test switch is operated, then there's no evidence of a wiring error and again the fitting should still work.

I think we've gone as far as we can go with the evidence available and investigation with test equipment is now needed to make any useful progres...

Yes thanks everyone, our contractors are coming in Monday to take a look as they have done some work on the lights. I thought i would put it out there just in case there was an easy fix without me calling them.

 

[westward10]

Let us know the outcome it is most intriguing.

 

[Bobster]

Open the fitting up and measure the voltage present with the MCB off and on

 

[Stspark]

Interesting post. As previously commented on by others. I'd be looking into the key switch possibly switching incorrectly perhaps the switch feed, strange that although the battery is charged it does not illuminate when power is cut.
I've previously seen like for like lamp changes cause electronic ballasts to become faulty on em lighting. They can be high maintenance sensitive bits of kit