Meter for electricity usage

[Jupiter01]

I have an annex which is fed from a sub main in the main house. There is an armoured cable which goes from the house to the annex and is connected into a consumer unit in the annex.

How can I install a meter in the house which allows me to record the units/cost of electricity consumed in the annex?

Thanks in advance.

 

[ban-all-sheds]

First question - why do you want to record the units?

Is it just for your own interest, or because you want to bill whoever is using the electricity?

 

[Jupiter01]

For my own interest. I use it as a gym and want to understand how much electricity is being used.

 

[ban-all-sheds]

Then just buy a meter that's safe and reasonably accurate, and put it before the cable leaving the house.

Or if there's space, put a DIN-rail one in the CU in the annex.

Or look at what there is out there and possbly just do a calculation. Mostly lighting?

 

[garyo]

You could try a clamp on usage meter. The type that the electricity providers were all giving away for free a few years back. Like this:

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/133041755211

 

[donrkebab]

You could try a clamp on usage meter. The type that the electricity providers were all giving away for free a few years back. Like this:

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/133041755211

Just about to say exactly the same thing. Great minds and all that

 

[Jupiter01]

Thanks for the responses.
With the clamp on meters, can I attach the clamp/sensor around the thick armoured cable?

Also how accurate/inaccurate is this to the meter option? And can someone please provide further guidance on the types of meter and how easy they are to wire in.

Thanks again

 

[donrkebab]

Thanks for the responses.
With the clamp on meters, can I attach the clamp/sensor around the thick armoured cable?

No it needs to go round a single core of the live cable.

Also how accurate/inaccurate is this to the meter option? And can someone please provide further guidance on the types of meter and how easy they are to wire in.

The clamp on is easy, but needs space to access a single core of the cable, fit the clamp and leave everything safe.
The traditional meter has to be connected in the same manner as your main meter.

 

[Jupiter01]

I’m unclear on how I would achieve this with an armoured cable? How do you suggest, I expose the live wire for clamping purposes?

 

[ban-all-sheds]

With the clamp on meters, can I attach the clamp/sensor around the thick armoured cable?

No - it needs to go round either L or N, not both.

Also how accurate/inaccurate is this to the meter option?

AIUI it depends on the size of the load - at low levels of use they tend not to be very accurate.

And can someone please provide further guidance on the types of meter and how easy they are to wire in.

With all due respect, if you have to ask that you should probably not be attempting this - if you had the necessary skills you'd know that you'd be able to do it.

Where does the SWA originate at the house end? Is it glanded into the CU, or is there a junction box? Will it need to be moved and glanded into something else?

If you put a DIN rail one in the annexe CU do you have suitable cable?

 

[donrkebab]

The normal method would be to make off the armoured cable into a box/trunking, say 150x150x150, this would big enough for the clamp. And the cable continues though the box to the supply point.

 

[winston1]

Also how accurate/inaccurate is this to the meter option?
Thanks again

They are not accurate. They measure current only. To accurately measure power used you need to measure current, voltage, and power factor.

 

[donrkebab]

The normal method would be to make off the armoured cable into a box/trunking, say 150x150x150, this would big enough for the clamp. And the cable continues though the box to the supply point.

Can you get a photo of both ends of the swa showing how the gland is terminated? Might be able to make something work, but this not really a diy job.

 

[Jupiter01]

I’ve re-wired a whole house not long ago. Not claiming to be an expert but not a complete novice either. I’ve just not done anything like this before and hence the questions. Thanks for all the help and I will post some pics

 

[ban-all-sheds]

I’ve re-wired a whole house not long ago.

What part of the UK are you in?

When you rewired, how did you go about deciding what cables and protective devices to use? Copying what was already there was not an option because it became your responsibility and what was there might have been wrong.

Did you know which circuits could be ring finals and which could not, and what the advantages and disadvantages of each are? Copying what was already there was not an option because it became your responsibility and what was there might have been wrong.

Did you know that the way in which cables are installed affects how much current they can carry? Copying what was already there was not an option because it became your responsibility and what was there might have been wrong.

Where cables need to be joined, did you know how this should be done / not be done and in what circumstances were different methods acceptable?

Can you identify extraneous conductive parts, and did you know the requirements for main and supplementary bonding of them?

At the time you rewired, which circuits should have been RCD protected?

What testing did you carry out after the installation? What sequence did you do them in and at what point did you energise the installation, and for each test did you know what was being measured, why it was important, how you would carry out the test, and with what equipment, and what sort of results you would have expected to get if everything was OK?

What did you do about an EIC for the work?