Installing a sub-main advice

[edwardings]

I've achieved planning permission to seperate part of my house, so I want to get the ball rolling and sort the electricity.

This section of house will be rented out and the new tenants will be responsible for paying their bills.

Is it possible to have two meters in one electricity cupboard? Then run the sub-main cable through my house (15-20meters) to the new consumer unit.

Also what size cable would be required? so I can get an idea of costs. As a rough guide the demand will be...

x 2 Dimplex DuoHeat 2.6KW
x 2 Dimplex Panel Heaters 2.0KW
x 1 Towel Rail 400Watt
x 1 Immersion supply 3.0KW
x 1 Electric Shower 9.0KW
x 1 Electric Cooker
x 2 Radial Circuits
x 2 Lighting Circuits

Thank You

 

[Hibbo]

I think you need to consider if your current supply can handle two separate properties.

would to not be better to get the DNO to install a new supply to the 'new' property. This will then be completely separate with the tenants having their own meter on the property.

 

[plugwash]

The first thing to decide is whether you want to go for private metering (e.g. you buy electricty and resell it to the tennant) or seperate supplies from the DNO.

Private metering is likely to have much lower initial costs but could leave you holding the bag if the tennants screw with thier metering or plain refuse to pay. It could also potentially blow your service fuse depending on it's rating and how heavy the loads are in the two sub-properties. It may also put off some tennants (you aren't supposed to make any profit sold on electricity for domestic use but some landlords do anyway) and will create problems if you ever want to sell the two parts of the property seperately.

If you want seperate supplies you will need to discuss it with the DNO. It is their call whether the incoming service cable is up to the task of supplying two service fuses or whether you need a new cable (and in rural areas even a new transformer which can make things really expensive). Whether a new cable is needed is likely to impact the easiest location for the new meter.

Is gas an option? I know i'd consider an all electric property to be a major down point as a tennant.

As for the cable size for a submain it will depend on what rating you chose for the submain (I'd suggest 80A given that it's all electric at the other end) and how you decide to split the volt drop budget (rememer it's the total volt drop that must be within what the regs require so having more volt drop on your submain means you can have less on the final circuits and vice-versa) but I'd guess 16mm or 25mm would be about right. I'd go for 3-core SWA, the earthed metal means the submain doesn't need to be RCD protected (and you REALLY don't want a submain like this RCD protected) and the full-sized earth means it's no problem for bonding conductors to be connected to the submain.

 

[edwardings]

Thanky you for your input, much appreciated.

would to not be better to get the DNO to install a new supply to the 'new' property. This will then be completely separate with the tenants having their own meter on the property.

I have phoned EDF and they wanted a minimum of £750 for the new supply and that was without them even looking. Like all things i'm guessing the price will go up.
I've priced up 25mm SWA and it would cost £200, so then all EDF need to do is fit a new meter. Of course this depends on them agreeing the supply is 'man' enough, which is the next step I need to find out.

(and in rural areas even a new transformer which can make things really expensive). Whether a new cable is needed is likely to impact the easiest location for the new meter.

I do live in a rural area, but there is already a newish transformer yards away, so I don't see this being a problem. The only additons to the grid would be the cooker and storage heaters, if I decide on that route.

Is gas an option? I know i'd consider an all electric property to be a major down point as a tennant.

Gas is an option, but i'm trying to decide if its worth the £3k its going to cost to install a CH system, plus the hassle of a new gas supply. Then you have the servicing costs of the boiler. Therefore i'm edging towards the storage heaters, as there cheaper to install and virtually zero maintenance costs involved.
I think I might get the electrician to install supplys for storage heaters and decide at a later date.

 

[electronicsuk]

Thanky you for your input, much appreciated.

would to not be better to get the DNO to install a new supply to the 'new' property. This will then be completely separate with the tenants having their own meter on the property.

I have phoned EDF and they wanted a minimum of £750 for the new supply and that was without them even looking. Like all things i'm guessing the price will go up.

I think you'd be mad to turn that price down. It will be far more sensible to fit a second DNO supply to what is, really, a completely separate property. Moreover, what happens if/when you want to sell? Your prospective buyer may not be interested in entertaining the electrical problems of the tenants in your other property.

 

[ban-all-sheds]

Gas is an option, but i'm trying to decide if its worth the £3k its going to cost to install a CH system, plus the hassle of a new gas supply. Then you have the servicing costs of the boiler.

Your prospective tenants won't care about any of that.

Therefore i'm edging towards the storage heaters, as there cheaper to install and virtually zero maintenance costs involved.

But they will care about their higher running costs and major impracticality.