Dedicated Mains Quick Questions

Hi there,

I am having an electric car charger point fitted in a couple of days and they will fit a seperate consumer unit in the garage taken off the main incoming feed which is located need the garage on the outside of the house. My living room where the HiFi is is situated directly behind the wall where the electric car consumer unit will be fitted so naturally I asked the question wether at the same time if they could take another feed into another consumer unit so that I can run the HiFi on a dedicated circuit. They said there should be enough room in the meter cupboard to fit all of the stuff required.

I have read a lot on the forum over the past few years and reread yesterday and the previous day. I just want to check I have the right idea from the experts here who have already gone down this route.

  • Run a seperate 16mm sq Earth to the HiFi Conumer Unit and another to the Car Charge CU. So effectivly 2 Earth cables, the key being 1x 16mm for the HiFi.

  • Run a seperate Live for the Car Charger and Hifi, HiFi one being as big as possible??

  • HiFi consumer unit having 50amp type C breakers on each of the circuits.

This will be as far as I go in this stage. stage 2 which will be in the new year will be CU through to sockets!

Thanks in advance and apologies if I have got the wrong end of the stick! The Electrician was very ameanable and seemed interested in what i was suggesting and seem happy to do it whatever way is best. Everything i mentioned above seemed to amke sense to them but obviously there are many different ways this could go down!

The electrician will need to split the meter tails with a Henley block. In this case they would be split three ways, house, car and hifi. The cables used for this are massively thick and are, I think, determined by the regs.

Make sure that the Earth for the hifi CU runs back to the meter and does not piggy back off the existing unit. Ask for a nice thick wire. My CU has a 50amp type C breaker so that should be fine.

When you come to install the wiring from the new CU to the hifi, make sure you go for 10mm2 cable.


32amp type C is what Naim recommend if you want specifics.


I agree, 32amp is more than enough, and what you are doing is protecting the cable


Thank you for all of the replies, I have spoken once again to the electricians and just forwrded this info. Seemed to make sense to them anyway!

This is the design of what I had done for my dedicated feed to my Hi-Fi.


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16mm is thick stuff, even 10mm is above the spec that a wall socket it designed to accept, so you should make sure that what you are proposing is physically possible.
If you want more than one socket, daisy chaining sockets in the usual way means putting two cables into each connection, when even one is a tight fit. A single socket with a decent quality mains block is a simpler solution. Either way, you need to think the whole thing through before your electrician starts the installation.


I read that as 16mm2 earth cable between the new CU and the earthing block at the meter cupboard / incoming feed so all should be fine.

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Ah, yes! I think you’re right. 16mm tails would be about right.

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Thanks again everyone for all of your input! The install will be in the new year. I note you can get plug sockets that are HiFi designed so take the thicker cables easier. Furutech make some I think. Not sure on peoples opinions, I was going to use unswitched MK ones but maybe if I go for a ring these Furutech types would be better…

I guess I need to read up on Radial vs Ring also over Christmas, I understand on here there are people who favour both types!!

Radial is normally recommended, so you might have 2 or 3 radials each going to an unswitched socket, or have 1 radial going to a socket and use a mains block. I think here the most important thing is to have thick earth, with all earth cables the same length which you don’t get in a ring, but do in a good mains block

What makes you believe earth cables need to be/are best all the same length?

Contactum and GET both make sockets that will handle 10mm cable, not sure about MK

Something to bear in mind with the Furutechs is that the two sockets in a double are independent of each other, and have to be wired as two singles. So you need to consider whether it’s possible to daisy chain the cable, or run two.

The recommendation for mains blocks is to have a star network for earthing . I then inferred that, possibly wrong, in which case I’m sure someone will correct me😳

Some of the power block brands have adopted this so called ‘star’ earth for marketing blurb.
Star earthing or grounding is important but this is in the audio signal area, it’s a single point to bring all the signal grounds, or -ve as Naim label them, to one single point.
The power earth connections, in most part, simply connect the case body to power earth & are for electrical safety. Yes it’s OK to have them in a ‘star’, the power industry call this a radial connection, & truth be told it’s more beneficial to wire the socket L&N in radial than it is the E earth.

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If you check the manufacturer’s website for the sockets, it should give you the cable capacity for each socket. For example, I used Siemens sockets that could take , 1 x 10mm2 or 2 x 6mm2.

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