Power supply to sockets tripping out.

[Mick]

Hi all, I live in a modern 1 bedroom flat. A problem that has developed is the power plug socket sometimes trips out. I can then simply re set the trip switch and power is restored. It has happened at night when little but standby is being used or when my desktop computer is on then it causes all sorts of problems.

From the label on the unit it is a MEM LB6301 It has separate trip switches for: Bathroom Shower - Bathroom Towel Rail - Sockets - Cooker- Water Heater and Smoke alarm.

The only one that has tripped in the 6 years I have been here is the socket circuit.

This is an Housing Association property, but I would like to make sure it is not my equipment before reporting anything to them, in case they just say it must be my computer type equipment .

I have been disconnecting things to see if I can tie it to ant one piece of my equipment, it has still tripped with all the computer plugs removed.

It has been suggested the trip switch could be too sensitive?

It can be weeks between this happening or like today twice in one day.

If no fault can be found should I use Uninterrupted Power Supply battery unit to protect my computer? Thanks for reading. Mick.

[Tim Watts]

On Thursday 21 November 2013 21:40 Mick wrote in uk.d-i-y:

I would report it to the HA if you think you've removed the possibility that it's your stuff plugged in.

An elecrician with a "Megger" can test the RCD side in minutes and the rest of the circuit fairly quickly.

[John Williamson]

It's possible to check actual earth leakage with the right meter.

You could beg, buy or borrow one of these:-

And test the suspect circuit.

There's also a go/ no go plug in tester in the same site. Most good electrical factors will have one or more types at about £25.

Always a good idea unless you're using a laptop, in which case you've already got one.

[Martin Brown]

You can safely measure the resistance from live to earth on anything you can unplug. The same sort of test can also be done on the mains wiring, but that part is best left to a pro with the right equipment.

It is more likely that somewhere there is an intermittent leak to earth and the trip is genuine. Kettles are likely appliance intermittent trip contenders since it can reseal the leak. This sort of fault can also occur in a damp atmosphere when moisture gets into things.

A good idea if your local power is dodgy, but you should probably get someone in to look at it. Tripping like that might mean that somewhere there is something nasty going on and it will only get worse.

[Dave Liquorice]

Agreed.

We don't *know* what is tripping. I get the impression it's a MCB on the socket circuit. Rather than a RCBO on the socket circuit or a RCD feeding more than one circuit. Clarification from OP required.

Judging by the OP's description there appears to be only minimal knowledge of electrical instalations. I'd recomend that the OP gets onto the HA to send an electrician round to look.

If it's and RCD of some sort tripping and there are more than half or dozen or so bits of kit with SMPSU's plugged in then the cumulative leakage of each one might be pushing the RCD close to tripping. A slight mains blip or other state change could then trigger it.

[Martin Brown]

You can safely measure the resistance from live to earth on anything you can unplug. The same sort of test can also be done on the mains wiring, but that part is best left to a pro with the right equipment.

It is more likely that somewhere there is an intermittent leak to earth and the trip is genuine. Kettles are likely appliance intermittent trip contenders since it can reseal the leak. This sort of fault can also occur in a damp atmosphere when moisture gets into things.

A good idea if your local power is dodgy, but you should probably get someone in to look at it. Tripping like that might mean that somewhere there is something nasty going on and it will only get worse.

[Brian Gaff]

If its cocking up the computer then yes, but I'd be a bit worried if it appears to be nothing on the circuit in case there is a little critter chewing the cable somewhere with safety implications.

Brian

[Adam Funk]

...and not just to the safety of the critter!

[Bill]

A long time ago, 40 years, my mother volunteered me to check out a friends electrical problems. A circuit was off and there was a strange smell coming from the fuse box apparently.

The fuse box was a large cast iron affair with a lovely large lever on/off switch and ceramic wired fuses. I opened the lid and found the box packed with some old, and not so old, fried mice. They must have been coming into it for a while and getting killed. It was "interesting" removing all the frazzled corpses.

[Bill]

A long time ago, 40 years, my mother volunteered me to check out a friends electrical problems. A circuit was off and there was a strange smell coming from the fuse box apparently.

The fuse box was a large cast iron affair with a lovely large lever on/off switch and ceramic wired fuses. I opened the lid and found the box packed with some old, and not so old, fried mice. They must have been coming into it for a while and getting killed. It was "interesting" removing all the frazzled corpses.

[Adam Funk]

Ahem, interesting.

[Mick]

Thank you everyone for your help, I will contact them on Monday I wanted to try and make sure it was not something they blame me for!

Most worried about the computer as there are a few plugs in a multi socket, but it does trip still with all them disconnected.

Mick.

[meow2222]

which does not test ELCBs

NT

[meow2222]

tell us the exact markigns on the trip switch

not really. Theres plainly a fault somewhere.

NT

[Mick]

I cant see anything other than the make: MEM & LB6301

I phoned the Housing Ass, they said they would mark it urgent and someone would call within 7 days, and that if any of my equipment is causing it I will be charged for the call out. Mick.

[therustyone]

May be a neutral-earth short like the neutral wire insulation bared somewhere, or the earth wire being used instead of neutral in a socket. As the neutral voltage can drift around with time it may or may not trip the RCD at random.

rusty

[meow2222]

N-E voltage rises according to load, if trip times are during evening cooking then it might be that.

A multimeter can pick up on most leaky appliances, though not all. Theyre only a few quid for basic ones.

NT

[Dave Liquorice]

Unless I've missed it we still don't know what is actually tripping other than something protecting the socket circuit only as, IIRC, only the sockets go off. We don't know if that socket protection is an MCB or RCBO.

[Dave Liquorice]

What has the N-E voltage got to do with an RCD tripping?

Modern RCD's are current difference operated. They don't care what voltage is on the "flow" and/or "return" wires only what the current difference is between the two wires.

Ancient ELCB's were voltage operated and were prone to trips due to supply and/or earth problems. Voltage operated trips are pretty rare these days.

[meow2222]

If you connect N to E, return current through CPC is proportional to N-E voltage difference. In practice though typical V differences are enough to trip an RCD nearly all the time.

Maybe a photo from teh OP would tell us what sort of trip it is

NT