Emergency lighting in flats stairwell and entrance

[tangowaggon]

Hi Guys, although I've spent some years as a domestic installer mainly fitting showers and some domestic rewires, I now need to wire some emergency lighting in some flats that I have bought, but now am realising there is more to it than I initially thought.

My initial thoughts were to have all of the normal luminaires on timed movement sensors, such that there would be no wall switches at all and the circuit would be switched from a single switch next to the consumer unit and have the non maintained (individual batteries in each light) emergency luminaires wired to the same circuit.

All of the areas are lit by natural light such that turning off the main switch would bring on the emergency lighting as a test without leaving the place in darkness (assuming the test is done in daylight!).

a/ is there anything actually wrong with this approach

b/ what else do I need to do?

Call me tight but I don't particularly want to pay £95 for BS5266 for about a page worth of info on what is likely to be a one off job.
Thanks
Gary

 

[bernardgreen]

When you design and install the lighting on the communal areas you take on a legal duty of care that the lightning ( and failure of lightning ) will not contribute to any accident, harm or injury to people using the area.

So you have to get it right.

Motion sensors need to detect motion and have the lights bright before a person gets to a hazard, the top of a flight of stairs for example. That requires careful thought as to where to put motion sensors to ensure they detect children or small persons no matter which door they come out of.

One hotel I know found it cheaper and more reliable to put door sensors on all doors in a corridor than to fit enough motion sensors to ensure lights came on when needed.

 

[tangowaggon]

Thanks Bernard,
I was put onto the microwave? switched lighting by the guy at CEF which will essentially pick up any movement in the space, whether it is in line of sight of the detector or not. just read the advice document from the fire authorities and simply timed switches are not advised as they can be difficult to locate in the dark and they can switch off halfway through the journey to the exit if progress is slow or interrupted. Having stayed in apartments with this system I can very much identify with this. Another scenario is when someone else has activated the timer and left the area and you start you start your journey with lights on without resetting the timer and it times out halfway down the stairs.

The lighting suggested by CEF would switch on as soon as anyone opened a door into the hallway/landing, remain lit whilst any movement was detected and switch off at an adjustable time once movement ceased. fast lighting low energy or halogen bulbs would need to be used I guess.

It's mentions of a key operated switch that I am trying to understand fully, I guess the whole lighting circuit could be isolated by a key switch but this would cause difficulties with bulb changes (not that I ever make sure the power is of before changing bulbs! accept slap on wrists)

 

[bernardgreen]

Microwave sensors are much better than PIR in detection motion. ( they are in effect mini radar systems ). Even so they may not detect a door opening into an apartment, detecting only when somebody moves out of the door. This can be a confidence factor, the person has to be confident enough to move into a dark area before the light comes on for them. A button by their door that they can press for instant light outside before opening the door would help anxious people. It is not unknown for intruders to stand still at a door until the lights time out and then ring the bell in the darkness meaning the resident cannot see who is at the door.

 

[OwainDIYer]

key switches are fitted to the emergency lights and must not disable the non-emergency lighting.

If you want a single test point for the emergency lights then you need a 4+earth circuit wired as:

Perm live
PIR switched live
Emergency Live through a keyswitch
Neutral
+earth

Use the PIRs that can be wired in parallel to control the load, so that anyone anywhere on the staircase will (re) trigger the lights.

It can also be useful to wire a second button on the door entry handsets to activate the stair lights, then residents can turn on the lights from inside the flat when checking through the door spyhole for anyone on the landing.

Decent lights have a gear tray which plugs into connectors on the base: remove the translucent cover, undo one retaining screw and the gear train swings out and disengages from the power supply. The luminaire can then be relamped safely without disabling the supply to other fittings.

 

[bernardgreen]

There are advantageous in a five wire + earth system.

Permanent live to sensors
PIR switched live from sensors to control a contactor
Contactor switched live to lamps
Emergency Live through a keyswitch
Neutral
+earth

This means the sensors do not have to switch the full load of the lamps so they can be sensors with low switching ability. A failed to short circuit lamp will not damage any sensors. A fuse per lamp might be advantagous so that a failed to permanent short lamp will not prevent other lamps from operating.

A time of day switch and/or ambient light sensor can be fitted between the switched live from sensors and the contactor to prevent lights coming on if ambient light is adequate for safe use of the stairs hall area.

A failed lamp may stress the contactors contact but it will continue to operate.

 

[RF Lighting]

Bernard is spot on here, and if you rate your contactors for inductive load switching a failed lamp or even a failed fitting shouldn't do any damage.

You've done well tapping up the CEF lighting guy for advice, but I would strongly advise against buying your lights from there. They will sell you tamlite fittings which are dreadfully made, and will fail prematurely.

Stick with a known brand like thorn, and make sure you're installing high frequency control gear for years of trouble free operation.

 

[tangowaggon]

I was figuring on buying luminaires with built in sensors so no need for switched live in wiring.
What's the problem if the key switch disables the non emergency lighting if the stairs and landing are naturally lit during the day? or is it simply a regulation thing?.

Here's another one, If linked smoke detectors have 230v mains L+N +trigger in the 3+e wiring and I wir ethe lights as above ie no switched live needed, what's to stop me from using the 230v L+N in the smoke alarm circuit to power the lights?

 

[Iggifer]

I would strongly advise against buying your lights from there. They will sell you tamlite fittings which are dreadfully made, and will fail prematurely

I don't think I have read anything on this forum that I have agreed so wholeheartedly with. Absolute garbage. I took great pleasure in skipping some tamlite fittings recently.

The louvres on their 600x600 modular fittings fall to pieces the first time you take them down to retube. (Assuming you got them up in the first place)

 

[Iggifer]

Here's another one, If linked smoke detectors have 230v mains L+N +trigger in the 3+e wiring and I wir ethe lights as above ie no switched live needed, what's to stop me from using the 230v L+N in the smoke alarm circuit to power the lights?

If the smokes are on their own circuit the em lights will only come on in a fire no? A simple power failure to the lighting cct would not cause the em lights to come on

 

[RF Lighting]

I was figuring on buying luminaires with built in sensors so no need for switched live in wiring.

Where abouts in Yorkshire are you? Was it a chap called Phil from tamshite that suggested this to you?

It's madness. The fittings cost a fortune and they're rubbish, plus you'll have lights going on and off all over the place at different times and no proper lux level regulation.

Pulling in an extra core whilst you're doing the wiring isn't going to be difficult.

What's the problem if the key switch disables the non emergency lighting if the stairs and landing are naturally lit during the day? or is it simply a regulation thing?.

It's just poor design, and there's no need for it to be like that. What if someone turns the keyswitch off to test the lights and forgets to put it back on?

Here's another one, If linked smoke detectors have 230v mains L+N +trigger in the 3+e wiring and I wir ethe lights as above ie no switched live needed, what's to stop me from using the 230v L+N in the smoke alarm circuit to power the lights?

No, leave the smoke alarms alone. The general lighting and emergency lighting needs to be on the same circuit. I'm starting to get the impression that you're not really all that interested in doing the job properly.

 

[OwainDIYer]

Here's another one, If linked smoke detectors have 230v mains L+N +trigger in the 3+e wiring and I wir ethe lights as above ie no switched live needed, what's to stop me from using the 230v L+N in the smoke alarm circuit to power the lights?

The fact that BS 5839 Part 6 Grade D LD3 systems are intended for single family dwellings only and are unlikely to meet the requirements for a multiple apartment building.

Why would you have smoke detectors in a common staircase anyway? If you need LD2 or higher then you will need a full fire alarm system not mains smoke detectors, and if you have smoke detectors in all the flats interlinked you will have massive problems with false alarms.

Presumably the person responsible for deciding that smoke detectors are needed is competent and legally responsible under the Regulatory Reform Order and has carried out the requisite Risk Assessment?

 

[tangowaggon]

Quote:
What's the problem if the key switch disables the non emergency lighting if the stairs and landing are naturally lit during the day? or is it simply a regulation thing?.


It's just poor design, and there's no need for it to be like that. What if someone turns the keyswitch off to test the lights and forgets to put it back on?

If someone turns the keyswitch off and forgets to turn it back on, the emergency lights batteries will discharge and be useless in the case of real emergency, however if the main lights are not working, someone will notice this, report it and get them turned back on, so I would say that it is better to have them both on the same switch.

I'm starting to get the impression that you're not really all that interested in doing the job properly.

On the contrary, I'm wanting replies such as yours to be sure that I get this thing right, the BS 7671 regulations regarding segregation of emergency circuits etc would probably forbid this but in reality, if it is ok to take a spur from the lighting cct to power smoke alarms, what, in reality is wrong with wiring the lights and smoke alarms with 3+e as the loop and using the spare core as the trigger for the alarms?.

I probably would save myself a lot of time if I just took things as gospel and never tried to think outside the box.

If the smokes are on their own circuit the em lights will only come on in a fire no? A simple power failure to the lighting cct would not cause the em lights to come on.

No, I'm talking about using the permanent L+N in the smoke alarm cct to power the main and emergency lighting, if the power fails, the main lights go off, the emergency lights come on and the smoke alarms switch to battery backup. this has the advantage that if the single circuit is left turned off, the main lights will not work, a fault will be reported and the fault corrected by having the cct turned back on.
If the smoke alarm cct is left off and the warning "pips" are probably ignored or not heard from inside the flats then, again, the lack of main lighting will prompt the fault to be reported.
Similarly, if the cct is left off, the emergency lighting will eventually go out and the lack of lighting reported before an emergency situation occurs.

One suggestion was that the test switch for the emergency lighting was a 2 way switch that illuminated a neon when the main cct was off, perhaps a better solution would be to have the 2 way switch connected to a sounder/buzzer when in the off position, far more difficult to ignore.

In reality, even if the lights are coming on through the day when anyone uses the stairs, this is a block of 5 flats where foot traffic is minimal, not an office block,

http://www.qvsdirect.com/360-3M-Microwave-Motion-Detector-1200W-pr-25513.html
Failing to find suitable lights with combined motion sensors, this looks a suitable alternative?

PS thanks for the warnings about Tamlites, will avoid.

Read more: //www.diynot.com/forums/electr...ll-and-entrance.348054/#2608582#ixzz2F9Wu8P6p

 

[tangowaggon]

Here's another one, If linked smoke detectors have 230v mains L+N +trigger in the 3+e wiring and I wir ethe lights as above ie no switched live needed, what's to stop me from using the 230v L+N in the smoke alarm circuit to power the lights?

The fact that BS 5839 Part 6 Grade D LD3 systems are intended for single family dwellings only and are unlikely to meet the requirements for a multiple apartment building.

Why would you have smoke detectors in a common staircase anyway? If you need LD2 or higher then you will need a full fire alarm system not mains smoke detectors, and if you have smoke detectors in all the flats interlinked you will have massive problems with false alarms.

Presumably the person responsible for deciding that smoke detectors are needed is competent and legally responsible under the Regulatory Reform Order and has carried out the requisite Risk Assessment?

The system has been specified by the builing control officer such that there is a linked smoke detector on each landing, linked to a heat detector inside the door of each flat, each flat has a separate smoke detector system

 

[bernardgreen]

It would not be sensible to use the same neutral conductor for the lighting and the interlinked smoke alarms. The trigger signal uses the neutral as its reference and lighting currents along the neutral will cause a voltage drop along the neutral. This voltage drop will alter the potential difference between the neutral and the trigger at each smoke alarm. This may affect the triggering as the trigger voltage is often less than 9 volts so a one volt drop along the neutral will change the trigger voltage by more than 10 percent. When lights switch on inrush current along the neutral may create enough voltage drop to trigger some of the alarms. Also the high current as lamp burns out may do the same.