Emergency lighting on contractor switched lighting circuits

NigelMarsh · Jun 8, 2014

I have been asked to get the emergency lighting working at a nursery. They had a switch put in at the entrance to the building that switches off all of the lights in the building when they lock up at the end of the day. All lighting circuits are hanging off a contactor connected to this switch, so they are cutting power to the light circuit MCBs and pretty much simulating failed circuits when using this, "master" switch.

whoever fitted this switch saw this and wired all of their emergency lighting into its own circuit to prevent it kicking in when the lights are switched off in the evening.

this obviously makes the emergency lighting pretty much useless for its main function.

they don't want to get rid of the master switch, but the want the emergency lighting to kick in when it's local lighting circuit fails. Doh!

Any ideas on how this can be achieved without losing the master switch, even if it means switching all lighting off using a different method? I'm going grey trying to come up with a simple solution.

:banghead:

Plonker 3 · Jun 8, 2014

What's wrong the current set up if all the EM lights are maintained?

Guest77 · Jun 8, 2014

NigelMarsh said:
I have been asked to get the emergency lighting working at a nursery. They had a switch put in at the entrance to the building that switches off all of the lights in the building when they lock up at the end of the day. All lighting circuits are hanging off a contactor connected to this switch, so they are cutting power to the light circuit MCBs and pretty much simulating failed circuits when using this, "master" switch.

whoever fitted this switch saw this and wired all of their emergency lighting into its own circuit to prevent it kicking in when the lights are switched off in the evening.

this obviously makes the emergency lighting pretty much useless for its main function.

they don't want to get rid of the master switch, but the want the emergency lighting to kick in when it's local lighting circuit fails. Doh!

Any ideas on how this can be achieved without losing the master switch, even if it means switching all lighting off using a different method? I'm going grey trying to come up with a simple solution.

:banghead:

Feed the emergency lights from the feed side of the contactor from the MCB, you can even add the test switch for them at that point.

Knobhead · Jun 8, 2014

If it’s 3Ph feeding the lighting contactor you will need a phase failure relay to monitor each phase.

tazz · Jun 8, 2014

As post 3, utilizing a bank of grid em keyswitches......if there are more than one phase, the warning signs that 410v is present should be displayed.

Knobhead · Jun 8, 2014

And if one of the phases fails, what then?

tazz · Jun 8, 2014

I cant see 3 phases feeding individual lighting circuits via the contactor, so if one phase was lost then em lights on that circuit would illuminate, and normal lighting would go out.....unlike control, its not dependent one all 3 phases

Knobhead · Jun 8, 2014

The reason I bought this up tazz is I’ve had two phases fail feeding a lighting contactor. ⅔[SUP]rds[/SUP] of the place blacked out and no EM lighting. To be honest I pulled the fuses to prove a point.
I don’t know who designed the set up but I know there was an arse kicking party afterwards. I don’t even know why I got involved, lighting and small power wasn’t my job.

tazz · Jun 8, 2014

Can see where you coming from..but here any phase that fails, will bring on the Em internal battery on that circuit, so even if all phases go out, it should course a problem...if it was a sustained central battery system, then this would need fail safe features

UKMeterman · Jun 8, 2014

What about feeding the perm feed via a contactor that has the coil fed from the same supply?

tazz · Jun 8, 2014

UKMeterman said:
What about feeding the perm feed via a contactor that has the coil fed from the same supply?

Then you wouldn`t need a contactor

UKMeterman · Jun 8, 2014

Hi,
You have missunderstood, the em lights if they are the maintained type have a perm live feed and and a switched live feed. If the supply to daily switching contactor fails then the switched live drops out but the perm live from the local supply is still live, so the light is not lit even if there is a fault to the contactor. If you have a second contactor in the perm live, with the COIL fed from the same COIL supply as the day switching contactor then a fault will then cause the perm live to be disconnected and the EM run from it's battery.

tazz · Jun 9, 2014

Hear what you say...but the lights switching off with their charging lights still on, would be an indication of fault on daily switch feed, fault on perm feed would result in em coming on off their own battery.
Hope old diagram will show

[ElectriciansForums.net] Emergency lighting on contractor switched lighting circuits

Knobhead · Jun 9, 2014

tazz said:
Can see where you coming from..but here any phase that fails, will bring on the Em internal battery on that circuit, so even if all phases go out, it should course a problem...if it was a sustained central battery system, then this would need fail safe features

As I said, I had little to do with them but I think you’ve hit the nail on the head. There was a central battery room in each of the intake subs which fed out to the various plant subs.
I gave them a wide berth, the mates looked after lighting and batteries. The only time an electrician got involved was if one of the central lighting panels failed.