Electric Sockets

[tvmo]

Hello,

I seem to be having some problems in my house with the socket circuit.

1) A couple of the sockets will power a low voltage light but not a hair dryer 2) Switching on the dish washer, which is on a separate ring to the majority of the sockets in my house, causes frequency issues on my TV 3) The washer dryer frequently trips the electric.

Before I call an electrician can someone give me some ideas of where the problem could lie.

Thanks

[Tim Downie]

Are there any wall switches in the same room that turn these sockets on and off? If so, they're probably meant for lighting only.

Frequency issues? Don't understand.

Have you got an RCD in the fusebox or do you mean that it trips the regular circuit breaker? Not uncommon for heating elements in ovens and washing machines to "leak" to earth causing RCDs to trip.

Tim

[Tim S]

tvmo coughed up some electrons that declared:

Probably a loose connection. Might be other things, but if it were me, I'd isolate the circuit, prove it dead, and go round and tighten all the terminals starting with the bad sockets - ideally check the lot. At the same time, I'd look carefully and see if anything's got hot as this is a possibility - may need to replace anything which has overheated. Probably won't take an electrician long to resolve this unless it turns out to be a cable fault, in which case, it depends...

You mean interference? I'm guessing the mains filter in the dishwasher may have gone bad, but I don't really know for sure. How old is the machine?

Is it tripping an RCD or blowing a fuse/tripping an MCB?

Seems like you may have a combination of problems, hopefully reasonably inexpensive to rectify, but problems 1 and 3 demand urgent attention because something is clearly not happy and it's sounds unsafe. Don't use the problem sockets obviously until they're fixed.

Cheers

Tim

[meow2222]

Pretty good summary. Number 3 might be seirous, but more likely not a significant safety problem. If you dont know your MCBs from your RCDs, just post a pic of the fusebox.

NT

[James Salisbury]

Frequency issues, does the hight of the picture decrease / a lamp pluged in dim?

If so it sounds like you have a serious voltage regulation issue. Please send a picture of your fuse box, and you may wish to call your selectivity company to check their side of the supply.

[John Rumm]

What happens when you try to run the hair dryer?

You mean you get a noise pattern on the screen - say lines with bright speckles on them?

Trips what exactly? The circuit breaker for the individual circuit, or the RCD protecting a group of circuits or possibly even the whole house?

Bit more info required first. However these faults may well not be related.

[tvmo]

On one of the sockets it doesn't work, on another socket the hair dryer blows air in pulses, on the majority of sockets it blows air evenly

Yes, exactly - sorry about the poor description

The whole house trips.

Thanks

[John Rumm]

OK, probably worth noting that all these faults are probably unrelated.

This could be a number of things. The most likely being loose connections on the sockets - causing sparking and intermittent supply to the dryer. The lower power requirements of the lamp may mean less local heating and hence less movement of the wires.

Alternatively it may be you have a serious voltage drop issue. Either a section of seriously undersized cable in a circuit, or a high resistance connection. These options would fit the symptom better if the dryer was a type with soft touch controls (i.e. electronic rather than mechanical switching), where the low voltage might cause it to behave incorrectly.

*** in either case, this fault is serious and needs investigating as a matter of urgency ***

High resistance or arcing connections are a fire risk. I would suggest not using the sockets (and probably the circuit) in question until this is fixed.

Some more background here:

>> 2) Switching on the dish washer, which is on a separate ring to the

I would expect the mains input filter on the dishwasher, or possibly the noise suppression caps on the motor have failed. Probably not a house wiring fault - although it is possible it could be related to a bad connection on part of a ring circuit.

The washer dryer is probably faulty. It may be the heating element is leaking current to earth (not uncommon as they age), or water has got into parts of the machine they should not have.

The other possibility is that you have just have too many circuits on the same RCD and it is as a result pre-sensitised. In these cases the switching transients of things like thermostatically controlled heaters cutting in and out may be enough to cause a trip.

See the nuisance trips section of the RCD FAQ:

problem is compounded by you having a single RCD protecting all of the circuits in the house. This no longer considered and acceptable way of wiring, but there was a time where this was common. A consumer unit upgrade would separate the protection for the circuits into groups such that you don't loose all at once, and also reduce the likelihood of trips in the first place as a result of the cumulative leakage being excessive for a single RCD.

[Andy Wade]

It sounds as if this could be quite an old installation, so the single device might, perhaps, be a voltage operated ELCB.

[John Rumm]

Yes, good point. Not as prone to nuisance tripping though IME...

To the OP, when you reset the whole house, are you doing it on something that looks like:

(you will probably only see the front bit with the switch on it poking out of a box)

or have you got something more like:

(with an earth wire running to and from it as in the picture)