DIY Doctor

Main navigation

Best consumer unit for energy monitoring and potential solar PV

Postby Halsteads » Tue Oct 19, 2021 8:00 am

installing a ground source heat pump involves moving consumer panel to plant room. plan is to replace/upgrade from old Memera 2000. SSE/Bulb and local electrician all booked for the move.

question is, what's the best consumer unit for the job?


    – site is single phase supply
    – pump requires 'C' type MCB.
    – new consumer unit will continue to feed two smaller consumer units within the house, and another within the garage.
    – ideally, I'd like to be able to use DIN rail mounted energy monitoring devices and switches
    – big guzzlers include Kensa 13kW heat pump, electric Aga on 2 x 32 MCBs (hobs and oven)

at some point I plan to install solar PV which I assume will affect panel choice?
Rank: Labourer
Progress to next rank:
Posts: 1
Joined: Tue Oct 19, 2021 7:33 am


Simply Build It

Postby Mr White » Tue Oct 19, 2021 6:31 pm

As you require so much, I would suggest you ask the electrician to visit site, anything else is just guesswork.
Mr White
Rank: Project Manager
Posts: 1026
Joined: Tue Jun 20, 2017 9:54 pm

Postby ericmark » Tue Oct 19, 2021 8:20 pm

I had a clamp-on ammeter supplied by Scottish power calibrated in Watt hours and watts, it was to be clamped around the tails to the consumer unit, however monitoring all was rather pointless, as you could not work out what was using the power.

I also have some plug in devices, and they do have their uses, [attachment=0]Caravan-battery6_28-06-20.jpg[/attachment] this shows battery charger recharging caravan battery.

But in the main no useful data if I want to know how much power a bulb uses, it is written on the bulb.

I had two fuse boxes in last house each fed from a RCD, and when one tripped I lost two freezers full of food, so this house all RCBO which is the MCB and RCD combined.

The RCD comes at 4 types AC, A, F, and B, but the RCBO as a single width device comes as either type AC or A, so if you need type B then can't really use RCBO's.

The distribution unit used for domestic is type tested and have a maximum of 120 amp, in real terms 100 amp, the old Wylex fuse box main isolator was only rated 60 amp, so most home have a supply of 60 to 100 amp, there are the odd ones with split phase or three phase but these are rare.

EV charging points often require a type B RCD or a DC monitoring device to turn off supply should it exceed 6 mA, and depending on the earth type it also may need to turn off supply then earth if voltage not between 207 and 253 volt, also with solar panels often needs to turn them off if not between 207 and 253 volt.

So with a TN supply may need the special cut-out, and with TT supply special RCD's. Also with TT you may need double pole RCBO's and I know Wylex make them, but does not seem that fusebox makes them.

So there can be a huge variation in price with TT and TN, fusebox SPD can be as cheap as £35 but Wylex more like £100.

Also a huge variation in price of RCBO's fusebox down to around £15 but some can cost up to £35.

In the main it is a compromise, but some one needs to sign they have designed it all.
Rank: Project Manager
Posts: 2619
Joined: Fri Oct 02, 2009 8:49 pm
Location: Llanfair Caereinion, Mid Wales.

Display posts from previous
Sort by
Order by

  • DIY How to Project Guides
  • DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!

  • Related Topics