Emergency Lighting Circuits

[Midwest]

Having been at present place of work, for just overs a year now,just started to feel comfortable with the place. It’s predominantly a care home, and has all the normal infrastructure in place.

I've never down much work with emergency lighting, other than installing it. Can anyone explain the different types, we have some simple types that seem to be just fed from the mains, with their own battery packs etc. In the main building, the is a dedicated system, that is monitored by control panel in the plant room. The emergency exit lights, appear to have a low voltage supply, but would the actual emergency lights in each room be extra low voltage, and run off the battery pack in the main panel.

 

[westward10]

The ones with their own internal batteries are known as self contained and require no specific type of wiring system as the important parts are contained within the fitting. The two general types or category of these are non maintained normally identified as 0/180 where 0 means non maintained and 180 is a 3 hour duration. This type of fitting should operate upon failure of the local general lighting. The other type is maintained normally identified as 1/180 where 1 means maintained. These should be illuminated at material times either by being switched on with the general lighting or just permanently on. Operation of a maintained fitting upon failure of the general lighting is not so important. You used to have sustained fittings which were a mixture of non and maintained fittings but these have all but disappeared.
The other system sounds like a central battery system whereby the batteries are centrally located and the fittings they supply are known as slave luminaires. Wiring systems to the slaves must have fire resistant properties to maintain the system in a fire situation, BS5266:1 has a whole section dedicated to the wiring methods for this type of system. Often maintained (on at all times) reduces the need for control circuits through the general lighting should it fail and they are required. Central systems with permanently illuminated slaves are often known as floating so there is no loss of lighting on switch over from mains to battery upon power loss.
That's a brief summary

 

[Midwest]

Thanks for that westward. The ‘slave type’ we have come on during a power supply failure, I suspect, as not experienced a power failure yet. They are tested monthly by a test function on the main panel, which reports luminaire faults, and communication faults.

Interestingly, we had some new unconnected equipment installed recentl, whereby the installer thought it ok to take their supply from one of the exit signs. This has caused that section of EL to be left permanently on, not sure why. Perhaps the system senses some voltage drop, and thinks there’s a power failure?

Re the fire resistant properties of the cable supplying the slaves, believe it’s just lsf cable, but would need to verify.

 

[westward10]

Is it definitely a central battery system as there are some sophisticated central test panels for self contained fittings. The recent addition was it to a self contained fitting.

 

[Midwest]

Is it definitely a central battery system as there are some sophisticated central test panels for self contained fittings. The recent addition was it to a self contained fitting.

Not sure, it was the same circuit for the slave ones controlled by the main panel. That’s why I’m trying to understand these things.

There’s a DB next to the main panel, that feeds a local sw fcu. This in turns feeds a local control panel (not had the lid of that and there’s several of these panels around the building). This panel feeds the sector of EL, where the unauthorised supply was taken.

For some reason, the mcb (16A) in the DB was tripped for this sector. Only happened when we set the EL on test.

 

[westward10]

Easy to tell a slave fitting as they do not contain batteries. It is possible the Exit box is a self contained maintained fitting which was not operating at material times (was not illuminated) and they have put a link between L (permanent charge supply) and SL ( the switched supply to illuminate it). Linking these terminals will result in permanent illumination as a maintained fitting should.
Generally in buildings where the layout maybe unfamiliar to its occupants it is recommended Exit signed luminaires are maintained/illuminated at all times.

 

[Midwest]

Yep, normally the exit sign is illuminated. The addition to the circuit, this will make you chuckle, is a supply to an automatic door opener. They will be coming back to sort that out.

Just wondering how the EL is reacting to this?

 

[westward10]

If it is a 230v self contained light it shouldn't have affected it at all. If it has a tube in it they may have slightly dislodged it or it needs a new tube.

 

[Midwest]

If it is a 230v self contained light it shouldn't have affected it at all. If it has a tube in it they may have slightly dislodged it or it needs a new tube.

Sorry for lack of knowledge on this. The exit sign appears to be on the same circuit comms link as the slave unit. I’ll see what happens when they remove their supply. When we did our EL test, we had a tenfold increase in faults. All these units are LED.

 

[westward10]

Be interesting to find out.

 

[Midwest]

Be interesting to find out.

Large corporation, procurement is nightmare.

 

[Lister1987]

IET do a sparks guide to emergency lighting;

View: https://www.amazon.co.uk/dp/1785616137/ref=cm_sw_r_cp_awdb_t1_XfQ0DbYDNP0HN



Link is generic with no affiliation tracking.