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Topic Title: Lighting control panel - 2 sources of supply
Topic Summary: Can I have 2 sources of supply into a lighting control panel
Created On: 06 March 2013 09:02 AM
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 06 March 2013 09:02 AM
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orion83uk

Posts: 13
Joined: 04 December 2004

Hi everyone,

Looking for some design advice.

I have two distribution boards in my building services design; one will supply the internal lighting (DB-1) and the other will supply the emergency interior lighting from a UPS system (DB-2).

The idea is to have a control panel which will control both the general switching operation of the lighting (contactors etc) and the switching of the emergency lighting on/off when required. Is it generally acceptable to have 2 sources of supply entering a control panel such as this? Would it also be acceptable to, more specifically, have a light switch which will activate two seperate circuits (via a contactor) where one circuit is supplied from DB-1 and the other from DB-2.

The emergency lighting is, unfortunately, a mixture of maintained and non-maintained fittings hence why I have this slightly more complex arrangement.

Any advice you can give would be greatly appreciated.

Best regards
Stuart
 06 March 2013 09:11 AM
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AJJewsbury

Posts: 11679
Joined: 13 August 2003

From a BS 7671 point of view it sounds OK to me - provided you have suitable warning notices as per regulation 514.11. Certainly a light switch on one (6A single-phase) circuit operating a contactor which switches lights powered by another circuit or circuits (e.g. 20A 3-phase) is quite normal in commercial/industrial situations. Others might be able to say if there are other standards that cover such panel building.
- Andy.
 06 March 2013 09:19 AM
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orion83uk

Posts: 13
Joined: 04 December 2004

Thanks Andy for your extremely prompt reply. And thanks also for quoting the relevant section from the BS7671. I can forward this design quite happily now :-)
 06 March 2013 09:33 AM
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OMS

Posts: 19837
Joined: 23 March 2004

Is that design compliant with BS 5266 - UPS supply to non maintained luminaires sounds to me that you need comprehensive circuit failure relays in order to bring the non maintained to a maintained state in the event of a local loss of mains.

If it really is a UPS, rather than a central battery system, wouldn't you be supporting the general lighting ?

Regards

OMS

-------------------------
Failure is always an option
 06 March 2013 10:58 AM
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orion83uk

Posts: 13
Joined: 04 December 2004

Hi OMS,

Thanks also for your input.

Basically, from the UPS supported DB-2, there will be some circuits feeding LED luminaires which should be maintained in the event of power loss (maintained), whilst addtional emergency only (non-maintained) lumianires should also be brought in.

I realise there will need to be a substantial control system with a mains loss detection + circuit failure relays in place. However, worst case scenario, if the control circuit were to 'fail' on mains power being restored, no safety issue would become present. Basically you would just end up with some luminaires on unecesarily.

Thanks again.
 06 March 2013 12:39 PM
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OMS

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Originally posted by: orion83uk

Hi OMS,



Thanks also for your input.



Basically, from the UPS supported DB-2, there will be some circuits feeding LED luminaires which should be maintained in the event of power loss (maintained), whilst addtional emergency only (non-maintained) lumianires should also be brought in.

Not should - must be maintained so illuminated at all material times - along with fire rated independant cabling including the UPS supplies to the DB - with DB and UPS being installed into a low risk area. You may also have some certification problems regarding the "certification" of the luminaires.

Anything non maintained will of course need a means of operating on local lighting circuit failure



I realise there will need to be a substantial control system with a mains loss detection + circuit failure relays in place.

For sure there will - I'm not sure what you are trying to achieve actually, it's not a "standard" solution by the sound of it.


However, worst case scenario, if the control circuit were to 'fail' on mains power being restored, no safety issue would become present. Basically you would just end up with some luminaires on unecesarily.

In that failure mode, yes - but you may also have failure modes that deny the UPS supply to the (presumed) converted luminaires

Taken as suite of requirements including BS 5266 Parts 1, 7 and 8, BS EN 60598 - 2 - 22 and BS EN 50171 I think you are going to struggle with certifying this system.



Thanks again.


Regards

OMS

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Failure is always an option
 08 March 2013 12:39 PM
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orion83uk

Posts: 13
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Thanks OMS for the references. I'm going to be checking over them this afternoon.

"For sure there will - I'm not sure what you are trying to achieve actually, it's not a "standard" solution by the sound of it."

Thought it may help if I explained the 'surroundings'. Basically, this is a huge shed - approximately 110m long x 60m wide x 16m high.

Along the roof there will be LED high bays. Some of these will be fed from the UPS/battery emergency supply to be used also as emergency luminaires in the event of mains failure. These effectively form the open area lighting.

Around the perimter walls at approximately 2.5m, there are a series of LED bulkhead luminaires which are 'non-maintained' emergency fittings also fed from the UPS/battery system and of course will come on in the event of power loss. These effectively forms the escape route lighting.

None of the fittings chosen have built in emergency battery packs hence why a UPS/battery + control system is being considered.

Best regards
Stuart
 09 March 2013 01:30 PM
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gordon.s1

Posts: 105
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Hi there,
Out of curiosity which High Bay LED lights did you use and why ?.
What sort of light levels were you looking for ?.
Have been asked to quote for some thing similar and the cost of these LED units is really high compared to the new T5 units.

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 11 March 2013 08:47 AM
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orion83uk

Posts: 13
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Originally posted by: gordon.s1

Hi there,

Out of curiosity which High Bay LED lights did you use and why ?.

What sort of light levels were you looking for ?.

Have been asked to quote for some thing similar and the cost of these LED units is really high compared to the new T5 units.


Hi gordon.s1,

Admittedly capital cost isn't an issue for us on this project. The luminaire is the Siteco (Osram) LED High Bay, 280W version. We were aiming for 150 lux down a centre aisle of this particular building and it was achieved with only 12 of these fittings. Previously, the design was going to use metal halides, and the calculations showed that it would have required 14 x 400W fittings to achieve this. The reason for choosing these is maintenance related (and energy saving as a by product).

Regards
Stuart
 12 March 2013 01:18 PM
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OMS

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Originally posted by: orion83uk

Thanks OMS for the references. I'm going to be checking over them this afternoon.

"For sure there will - I'm not sure what you are trying to achieve actually, it's not a "standard" solution by the sound of it."

Thought it may help if I explained the 'surroundings'. Basically, this is a huge shed - approximately 110m long x 60m wide x 16m high.

OK - understood


Along the roof there will be LED high bays. Some of these will be fed from the UPS/battery emergency supply to be used also as emergency luminaires in the event of mains failure. These effectively form the open area lighting.

Right - obviously the circuit wiring of these will need to be fire rated to the durationof the system autonomy (ie one or three hours, with the latter being very difficult to achieve with common soft skinned cable types)

I presume these luminaires wil be on at all material times (ie when lighting is needed, and remain illuminated on loss of mains to the relevant circuits



Around the perimter walls at approximately 2.5m, there are a series of LED bulkhead luminaires which are 'non-maintained' emergency fittings also fed from the UPS/battery system and of course will come on in the event of power loss. These effectively forms the escape route lighting.

OK - first you need to know who the occupants are and if non maintained is acceptable - in this kind of application, maintained would be more usual - but it depends on the "occupant class".

Fire rated cabling as a prerequisite.



None of the fittings chosen have built in emergency battery packs hence why a UPS/battery + control system is being considered.

Yes, understood - to answer your first question, there is no limitation on the number of supplies in a panel - as long as you have adequate warning lables.


Best regards

Stuart


Regards

OMS

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Failure is always an option
 15 March 2013 08:17 AM
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orion83uk

Posts: 13
Joined: 04 December 2004

Thanks again OMS. Some good addtional 'food for thought' so to speak.

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