Rewire & Another blown shower switch

[swnshp]

Our house flooded in June last year, and the entire downstairs was stripped out. The electrics in the house where old, and so a rewire was performed at the same time, on the whole house, however:

1) We have no documentation or certificates to say this has been done, should we have had something?

2) The labels on the fuse box are incorrect (a new fuse box). Today, the shower switch blew, and an unlabelled MCB had tripped. The MCB labelled shower hadn't tripped, but I flicked it off manually while I investigated. I noticed that the upstairs 13A sockets at this point went off. I have now reset the MCB labelled shower and the upstairs sockets are working. Until I fit a new switch in the bathroom, I have no idea whether the sockets are on the same circuit (!!!???) or whether as I think, the labels are just wrong. This is surely bad news!

3) On the subject of the shower, they did not rewire this. This was previously outside of the normal fuse box, on it's own MCB and RCD. It's now part of the main box, however, the wires do not have appear to have been replaced. The cable running from the fuse box to the switch is of the brown and blue variety. The cable running from the switch into the shower is of the red and black variety. This is how it was prior to the rewire when the shower was fitted about five years ago. (I suppose I cannot guarantee that the fuse box to switch hasn't, but cetainly they shouldn't have fitted the red/black one, and I do remember this being these colours when we replaced the switch before the floods).

By the way, the 45A DP switch was from B&Q and only 2 weeks old, I fitted this myself 2 weeks ago. When it was switched on, it made a large bang and was stuck in the on position. I took the switch off and disassembled the unit carefully. All the springs where out of place, and some of the metal connections had come apart. There was no excessive blackness or any melting. The blackness was not on the actual connections the wire comes into direct contact with, but on some of the bits connecting to this. The previous switch had blackened at the Live load terminal, and melted. I stripped the wire back cutting off the black parts, before fitting the new switch. This terminal was still a shiny gold on the new switch today. I had noticed the last couple of days a minor spark when turning on the switch.

[John]

Why are you switching it off? Surely it is for isolation purposes. It all sounds very suspect.

[NOSPAMnet]

If I'm reading the OP correctly ( 45A DP) it's either a wall switch or a ceiling pull switch he speaks of so why should it not be switched off each time the shower is finished with .I must admit I don't always do that with my ceiling switch but a Triton engineer told me I should.although I'm not sure why . That switch isn't for isolation purposes .It has it's own fused ( well MCB) unit

[Dave Liquorice]

I couldn't work out what the OP was asking about...

An MCB does not provide isolation as they are single pole. Only a double pole device with appropiate contact spacing when open (>3mm?) provides isolation.

[NOSPAMnet]

The unit my shower is connected to is a Wylex unit which I think is DP.It has a plugin breaker which I remove after switching the unit off .

[Micky Savage]

What? it is not hard wired.

YOU NEED A SPARK... QUICKLY,

Micky Leeds . Yorkshire.

[John]

Sounds like it is switching with a load applied if the OP is getting a minor spark!>

[NOSPAMnet]

What on earth are you talking about ...not hard wired ?

[meow2222]

Great, one of these people that claim serious faults where none exist. You've replaced the switch, which hopefully B&Q will refund on, and you've swapped the CU labels. Now go away.

NT

[dicegeorge]

as electricity can kill if i was you i'd disconnect it and investigate further, maybe for months draw a circuit diagram, take photos, study electricity, talk to experts - amateur and professional etc (including paying money) but first disconnect cos: When it was switched on, it made a

sounds dangerous...

maybe its a fault with wiring, or a unit, or the first box, or your understanding, or a mixture, so as electricity kills i'd make it safe.

i've just got an old house with wiring which i dont fully understand, i pulled the fuses out one by one and if i couldnt figure what they did i left them out.

Luckily a previous owner had an big RCD fitted in front of the many ancient fuseboxes.

But it hasnt got any labels on it so i think i should get that replaced soon, and get a main isolator switch.

then continue tracing the many wires.

but as your made an unexplained big bang i'd get scared quick if i was you...

[george]

[George (dicegeorge)]

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 MAINTAINED

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?

Where can I get better lights than these i found at CPC?

Shouldnt they eventually be on a new circuit sharing with smoke alarms etc and without an RCD?

Where can i get an alarm for this new circuit which will go off if the electricity to it fails?

And how would I know if the emergency lights' batteries are flat or not charging?

thanks

[George (dicegeorge)]

you say:

as i too am trying to suss out wiring in my house i'd also suggest you draw your own wiring diagram on one bit of paper for the whole house upstairs and down using lots of different colours- which makes it so much easier when wires cross!

and on another bit of paper a diagram of your fuseboxes and pencil in your guesses about which fuse does what then test them one by one.

and get yourself a few of these:

MAINS TESTER £1.52 its quick to double check your sockets for missing earths etc...

[chrisj.doran]

20)

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.

You may be able to get them on eBay for a few pounds less, but they're all very similar.

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. Put it on any circuit that's unlikely to fail unnoticed for long enough to drain the battery. An alarm circuit would be a good choice.

Not sure, but look for "fridge alarms".

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.

Chris

[Dave Liquorice]

It means it is not on (emiting light) all the time, it only comes on whe= n the power fails. Maintained lights are on 24/7 irespective of the supply= status.

IMHO they are all much of muchness at around the =A315 mark non-maintain= ed. Go for one you like the appearance look of, some are a bit "industrial" =

for putting at the top of the stairs in a home.

That would be best, if your non-maintained emergency light comes on you =

know you have a problem with the smokes circuit as well. Not sure that

17th Ed will allow the use of a non-RCD circuit.

They have an indicator light but this probably only means the charger is= working rather than the batteries are OK. In commercial buildings you'll= find secret key switches (EMERG LIGHT TEST) that disconnects the power t= o the emergency light so it can be tested. In the home you could just flip= the relevant MCB.

[Andrew Gabriel]

MAINTAINED

> Manufacturer: ETERNA   Order Code: SR06603 Unit Price: £15.49 (£18.20)

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.

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.

[George (dicegeorge)]

thanks chris and dave and andrew, i'm now planning to get one of each in a few hours and then measure the charging current etc...

[chrisj.doran]

I've measured non-maintained one. With the battery fully charged it takes 14ma, or about 3.5W. Tomorrow I'll run it down and see what it takes when recharging the battery

As to where to connect it, I agree that Andrew's argument for putting it on the lighting circuit is also a good one. In practice it will probably come down to whatever circuit is easiest to tap into.

Chris

[Dave Liquorice]

I will agree with that as well despite saying put in on the smokes circuit earlier. The primary use of the luminaire is to produce light when the main lighting fails *for whatever reason*.

So some form of alarm for the smokes circuit is needed, it would be easy to have a small mains relay and use a NC pair of contacts to complete a circuit with a battery and self oscilating peizo sounder. Have the problem of knowing if the battery is good or not though. I wonder if you could "borrow" the inards of a smoke alarm, that does the battery monitoring and produces a decent sound. Using a relay again for mains failure detection.

Which will probably be the lighting circuit at the top of the stairs...

[Dave Liquorice]

Or if the mains fails at 0200 they'll have flat batteries by 0500 and up here in the winter it doesn't get light until after 0700... But it would make it safer when going to get the other backup lighting sorted out. Last time we had a nightime power cut the No.1 Daughter light failure alarm was

*very* effective...

Good pointer Andrew, though I'm surprised they rely on battery cooking rather than some form a "intelligent" charger. I'll be interested to see the results of Chris's charge cycle measurments.

[Andrew Gabriel]

I've got a small pile of ones removed from commercial premises because their batteries got to the "replace-by" date. (It's always much cheaper to fit a new emergency light than it is to buy replacement batteries, sigh). The long ones with 8W tubes are 5W standby, and the short ones with 4W tubes are 4W standby. Although the batteries are now well past their "replace-by" dates, they all still give full 3 hours, probably because they've been run down once a year (although I only have 2 connected up).