Potential overload of ring mains

[Callcom]

At a house viewing I saw a dozen electric radiators connected mainly by plugs into wall sockets, one or two (in bathrooms) connected to fused spurs. I calculated nearly 14Kw and I'm given to understand all these rads are connected to either of two ring mains with 32A breakers.

A quick look at the consumer unit showed all the powerful stuff on dedicated circuits, apart from washing machine, tumble dryer, dishwasher, steam oven, so these must be plugged into one or other of the two ring mains. There was no dedicated circuit for the electric rads.

I know you can have unlimited sockets for a floor area > 100m2, but I would have thought all those rads on a cold winter's day would cause tripping? I'm looking at having to re-wire if I go ahead with the house, unless anyone disagrees?

Cheers

 

[Deleted member 9648]

You'll need to investigate further, assuming the rads are on stats then some diversity may possibly be applied. It would be usual to have an electric heating system on dedicated circuits though, not on a ring for general use.

 

[Dave OCD]

It sounds like it to me as you describe it, obviously there would be some diversity on these heaters but it certainly doesn't sound properly designed.

 

[Pete999]

It sounds like it to me as you describe it, obviously there would be some diversity on these heaters but it certainly doesn't sound properly designed.

Certainly agree with that statement.

 

[Callcom]

You'll need to investigate further, assuming the rads are on stats then some diversity may possibly be applied. It would be usual to have an electric heating system on dedicated circuits though, not on a ring for general use.

Thanks guys, seems like my sinking feeling is justified. Funny thing is all the rads have moulded plugs so they are designed to plug in. It's going to cost a fortune to run a dedicated service I would have thought right round the house.

 

[Octopus]

I think you need more info ............ some of those wall mounted heaters are only 750w each!

 

[Billsays]

Got to be the most Expensive way to heat a house......Can central heating not be installed? (Gas or oil) If not maybe install economy 7 heating?

 

[Callcom]

I think you need more info ............ some of those wall mounted heaters are only 750w each!

Yes I saw some of them were lower than that, and then some a lot higher. I reckon they all add up to around 14Kw and are not on a dedicated circuit, and since they plug into wall sockets they must be on one or other of the ring mains, hence my concern.

 

[Callcom]

Got to be the most Expensive way to heat a house......Can central heating not be installed? (Gas or oil) If not maybe install economy 7 heating?

Unfortunately there's no mains gas. To install an oil tank and boiler plus a full system is going to cost thousands I would have thought.

 

[Pete999]

Yes I saw some of them were lower than that, and then some a lot higher. I reckon they all add up to around 14Kw and are not on a dedicated circuit, and since they plug into wall sockets they must be on one or other of the ring mains, hence my concern.

Not ring mains any more Callcom, Ring Final Circuit, RFC for short, not to confused with a Radial Final Circuit.

 

[Deleted member 9648]

Do you have info on the type/make of heaters fitted? Are they the (alleged) smart type or just ordinary panel heaters?

 

[Callcom]

Not ring mains any more Callcom, Ring Final Circuit, RFC for short, not to confused with a Radial Final Circuit.

Point taken - still the same problem though

 

[Callcom]

Do you have info on the type/make of heaters fitted? Are they the (alleged) smart type or just ordinary panel heaters?

Yes they are Haverlands. I've looked them up and they are thermostatic programmable, very efficient etc etc.

 

[sparksburnout]

Is there any evidence of problems? Sounds like you don't have too many options. Maybe you should get a condition report done?

 

[Callcom]

Is there any evidence of problems? Sounds like you don't have too many options. Maybe you should get a condition report done?

No not really - apparently the electricity does trip occasionally but sounds more like power cuts, during storms etc.

 

[davesparks]

It is unlikely to cause tripping of the mcb due to the diversity of the loads, however it is a pretty poor setup.

How well insulated is the property? Improving the insulation may reduce the amount of heat input required and thus reduce the problem and your electricity bills.

 

[Octopus]

Back to the OP:

Is this a house you are thinking of buying?

If so commission a local decent spark to do an EICR and don't be fobbed off with a drive past sub £100 report. A decent report, in your area is going to cost £150 upwards and take half a day or more.

You could specify, that the EICR looks closely at the electric radiators too, so you can get decent information too.

You never know, there could be a 2nd fuse board and the "old" storage heater circuits have been used.

 

[static zap]

It is unlikely to cause tripping of the mcb due to the diversity of the loads, however it is a pretty poor setup....Hi Bills )

Diversity produced by thermosts is OK , until
they are all synchronised by a Thermal effect ,like turning off
for a few days holiday -(with no background heating) .
Then coming back whens its cold and switching them all back on at same time (Just like a power cut)

 

[Callcom]

Well, Christmas over, with a house full, immersions on, all heating turned up, two ovens on etc etc, and not a hint of a problem. So I guess I'll just go with it for the foreseeable until and unless anything does happen. Bearing in mind we've had a few cold snaps, including the last couple of days, I'm optimistic that my concerns were unfounded. Thanks to all who took the time to reply.

 

[Taylortwocities]

If you want to do some checking by yourself, you could get a cheap clamp meter like this LAP Digital Clamp Meter 600A - https://www.screwfix.com/p/lap-digital-clamp-meter-600a/8906f
and keep and eye on what the actual load of each circuit is.

 

[Callcom]

That's a good idea, thanks!

 

[Callcom]

Had a look at clamp meters, great solution except you can only clamp individual conductors - apart from a Megger model which doesn't seem available any more. Individual conductors are only accessible in the CU, not sure if you could get the clamp in there. Splitting cables doesn't seem an easy option?

 

[Callcom]

Maybe the idea is a flexible adapter, a hoop you can unplug and pass behind the conductor and then re-plug, pushing the banana plugs at the other end of the adapter into your multimeter. Not cheap at £100+ though.

 

[Taylortwocities]

Individual conductors available in every socket. on a ring final the same current(ish) will be at every socket.
But there’s usually room for a clamp meter in the CU, One of the line conductors going into the MCB Is the usual place. There’s usually a short loop at that point.

 

[Callcom]

I hadn't thought about the sockets - presumably you'd need a plug-in module with split cables attached? Cheers

 

[Taylortwocities]

No, you won’t get any current there.
Unscrew the socket and access the conductors behind. But better and more accurate inside the consumer unit.

 

[Callcom]

OK, thanks for your help.

 

[DPG]

Take socket front off, clamp meter on live conductor. Don't do it using a 13A plug top as you will only see the current that the plugged in device is using.

 

[shaun1]

Or you can clamp the live meter tail to get total current. And then switch on one circuit at a time to see individual circuit currents.

 

[Pete999]

Had a look at clamp meters, great solution except you can only clamp individual conductors - apart from a Megger model which doesn't seem available any more. Individual conductors are only accessible in the CU, not sure if you could get the clamp in there. Splitting cables doesn't seem an easy option?

I have 1 of those Megger clamps handy bit of kit.

 

[Callcom]

Thanks for the suggestions, some good ones there. CU might be the best bet, though space is a little limited. I also thought you needed to avoid close proximity to other conductors as that might affect the magnetic field. I'll go for the cheap clamp meter off Amazon and experiment - though as I say there's been no tripping at all so far even with the system under reasonably high load (I'm not looking forward to the bill though..)

 

[Pete999]

Thanks for the suggestions, some good ones there. CU might be the best bet, though space is a little limited. I also thought you needed to avoid close proximity to other conductors as that might affect the magnetic field. I'll go for the cheap clamp meter off Amazon and experiment - though as I say there's been no tripping at all so far even with the system under reasonably high load (I'm not looking forward to the bill though..)

This is what you need, might find one on ebay, I still have mine.
http://www.biddlemegger.com/biddle-ug/Flexiclamp_200_UG.pdf

 

[Pete999]

This is what you need, might find one on ebay, I still have mine.
http://www.biddlemegger.com/biddle-ug/Flexiclamp_200_UG.pdf

FLEXICLAMP200 NEUTRAL | Flexiclamp 200 multicore clamp meter | 241-4007 | Welcome to RS Online - http://in.rsdelivers.com/product/neutral/flexiclamp200/flexiclamp-200-multicore-clamp-meter/2414007

 

[GeorgeCooke]

Yes they are Haverlands. I've looked them up and they are thermostatic programmable, very efficient etc etc.

ALL electric heaters are 100% efficient so that is very misleading etc etc.

 

[Taylortwocities]

. I also thought you needed to avoid close proximity to other conductors as that might affect the magnetic field. .)

The single conductor that you measure is enclosed by the meter clamp jaws. So other influences are not a problemo.

 

[Callcom]

Thanks again for the suggestions, I'll have a look at the Flexiclamp.
Yes that's right about the 'efficiency' claims. I got the impression that Haverland were suggesting they could produce more heat per amp, but how you would measure that I'm not sure, without some sort of comparison. They certainly chuck out the heat and no-one's been cold, but as I say we'll see what the elec bill is like before celebrating.

 

[Callcom]

Can't find a Flexiclamp 200 anywhere, even Ebay. I guess one might come up sometime, in the meantime I'll go for the cheapo Amazon one - thanks Taylortwocities for the advice re ohter influences

 

[Pete999]

Can't find a Flexiclamp 200 anywhere, even Ebay. I guess one might come up sometime, in the meantime I'll go for the cheapo Amazon one - thanks Taylortwocities for the advice re ohter influences

Still got mine?

 

[davesparks]

Or you can clamp the live meter tail to get total current. And then switch on one circuit at a time to see individual circuit currents.

Which is a far more sensible suggestion than messing around trying to get a clamp meter into a consumer unit, or measure half the current at a socket!

 

[davesparks]

Individual conductors available in every socket. on a ring final the same current(ish) will be at every socket.
But there’s usually room for a clamp meter in the CU, One of the line conductors going into the MCB Is the usual place. There’s usually a short loop at that point.

There’s an obvious problem with this suggestion, and other methods of measurement are safer to carry out.