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Andrew Gabriel

In article ,
writes:
On 5 Sep, 21:44, "George \(dicegeorge\)"
wrote:
Which Emergency Lighting shall i buy online tonight for my house so I could
get safely downstairs if the mains fails?

EMERGENCY EXIT LIGHT, 8W MAINTAINEDhttp://cpc.farnell.com/SR06603/electrical-lighting-security/product.u...
Manufacturer: ETERNA * Order Code: SR06603 Unit Price: £15.49 (£18.20)

*ETERNA YD630NM *EMERGENCY LIGHT, 8W NON-MAINTAINED *£13.94 *(£16.38)

What does 'non-maintained' mean?
A "non-maintained" one comes on only when the mains fails. A
"maintained" one can additionally be wired to a switch so that it
doubles as an ordinary light, but it comes on/stays on if the mains
fails. As they're not very bright, the "ordinary light" feature is
only useful in small spaces or for permanently illuminated exit signs.
Where can I get better lights than these i found at CPC?
You may be able to get them on eBay for a few pounds less, but they're
all very similar.
Shouldnt they eventually be on a new circuit sharing with smoke alarms etc
and without an RCD?
The pedants will insist on a separate circuit, but that's only for
ease of testing in a public building where it's inconvenient to turn
off all the power.

No, they should be on the same circuit as the ordinary lighting in
that location, so they come on if that circuit fails. They need a
separate switch for test purposes - that's normally a keyswitch in
commercial installations so it's not inadvertently switched off.

Where can i get an alarm for this new circuit which will go off if the
electricity to it fails?
Not sure, but look for "fridge alarms".
And how would I know if the emergency lights' batteries are flat or not
charging?
They have a charging LED (which is often so bright you can see where
you're going at night . You are supposed to test them once a month
by turning the power off, so it may be convenient to put it on a fused
(but not switched) spur. In a public building you're supposed to check
they will run for an hour.

Check the instructions, but to get longest battery life and to test
them, you should run them for their rated duration (normally 3 hours)
about once a year (unless a power cut does it for you).

There are some aspects which make commercial emergency lighting less
than optimal in domestic situations...

They'll operate when the mains fails until the battery goes flat.
If the mains fails at 3pm for 12 hours, the battery will be going
flat just as the light might start to be useful. They are intended
to give cover to evacuate commercial premises, whereas you probably
want to carry on living in your house during a power cut. They are
not a substitute for having torches or other lighting sources, but
will protect you from sudden unexpected darkness.

In times when people are concerned about standby load, their
standby load stinks. This is because they recharge their battery
at high current (the standards require them to be fully recharged
and ready for another power cut quite quickly), and they don't have
any logic to stop charging when the battery is charged (they use
batteries which don't mind this and just get warm). The charging
circuitry is also very inefficient. In commercial environments,
no one will pay extra for a more efficient model, so no one makes
them (AFAIK).

They look ugly.

--
Andrew Gabriel
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