Can I supply electric to a 2nd garden chalet from my existing supply? main house fuse is 100amp

[RobDorset]

Hi All, 

 

I have a large Victorian house currently arranged as 2 flats with separate kitchens but both coming off 1 electric supply.

 

2 washing machines, 2 kettles, 2 toasters, 2 microwaves, 2 air-fryers, 2 fridge/freezers, 5 bedrooms in total,  1 sitting room in total 

 

1 x 4 ring induction hob 

 

heating and hot water mostly gas but has electric immersion cylinder back up for Hot water. 

 

Also have a garden chalet with kitchenette and electric shower.  Chalet connected to house supply via armoured cable. 

1 single ring induction hob,  1 kettle, 1 toaster, 1 electric fire, 1 combination microwave. 1  electric shower, 1 small fridge/freezer

 

 

Can I supply a 2nd garden chalet from my existing supply?  main house fuse is 100amp 

 

2nd chalet to have  1 x immersion cylinder,  1 x kettle, 1 toaster,  1 x combination microwave,  1 x 2 ring induction hob. 1 x saniflo pump 

 

All light bulbs are the new low energy ones.  

 

I built the log cabin / chalet myself all apart from the electrics and am keen to do another one but in brick/blocks.  

 

Thanks in advance for any help/tips/advice...   (PS: please not too much technical jargon.  my understanding of electrics is limited) 

 

RobDorset 

[ProDave]

I assume these are let as separate units or a hmo?  It would be most unusual to have 2 separate flats sharing one supply. Who pays the bill? let alone a third unit sharing the same supply.  Now you want to add a 4th.

 

Forget lighting.  It is the big loads that add up.  

 

If you are serious about this I would first shift everything that can be to gas. So gas hobs, gas water heating and showers running from gas HW.  Then you are only looking at other stuff on the limited electricity supply.

 

Why are you not doing this properly and getting a separate supply to each unit?

[SteamyTea]

Probably pushing it a bit. Mainly because of the electric showers.

 

Have a look at 'diversity'.

[RobDorset]

18 minutes ago, SteamyTea said:

Probably pushing it a bit. Mainly because of the electric showers.

 

Have a look at 'diversity'.

 

19 minutes ago, ProDave said:

I assume these are let as separate units or a hmo?  It would be most unusual to have 2 separate flats sharing one supply. Who pays the bill? let alone a third unit sharing the same supply.  Now you want to add a 4th.

 

Forget lighting.  It is the big loads that add up.  

 

If you are serious about this I would first shift everything that can be to gas. So gas hobs, gas water heating and showers running from gas HW.  Then you are only looking at other stuff on the limited electricity supply.

 

Why are you not doing this properly and getting a separate supply to each unit?

I'm not doing anything improperly.  electric was installed by qualified electrician and signed-off properly.  Good advice about using gas.  thanks.  

[RobDorset]

On 18/08/2024 at 13:51, RobDorset said:

 

I'm not doing anything improperly.  electric was installed by qualified electrician and signed-off properly.  Good advice about using gas.  thanks.  

SSE have today quoted me £21600 to install a separate supply.  Hence my original question.   

[RobDorset]

SSE have today quoted me £21600 to install a separate supply.  Hence my original question.   

 

On the subject of "Diversity"  I guessed around 20%  ie:  I can connect 20kw to an 18kw supply as the maximum I would ever use would be  16kw. 

 

SSE advised me that the "diversity" at my property would be  22%   

 

They also said I can keep the electric shower and my 1st chalet but that I can only use lower power such as lights,  TV, etc in the 2nd one. 

 

They told me that the highest drain things are instant heat such as electric showers,  electric heating and electric cooking.  everything else is 

comparatively low KW.  

[Mike]

You could also swap the induction hob for a model that has built-in power management (which shares the power between the rings), if you don't have that already. These use 16 or 20 Amps, rather than the 32A of a regular hob. Of course things won't cook so fast if you have all rings running flat-out.

 

Also consider a load-shedder (such as the Hager 60060), to temporarily cut the supply to a number of selected circuits if the total load approaches the maximum. However you need to be able to shed enough load - the immersion heater and washing machines could be cut without inconvenience, but probably not much else, but that may be enough. You'd need one in each consumer unit that has loads that you wish to shed.

[torre]

Maybe SSE would upgrade your existing supply to three phase at a reasonable cost (versus 21k!) and that might give you more options, like splitting into three single phases?

 

(Bear in mind I'm a light bulb changer and plug wirer, I'm not in the trade!)

[RobDorset]

6 minutes ago, torre said:

Maybe SSE would upgrade your existing supply to three phase at a reasonable cost (versus 21k!) and that might give you more options, like splitting into three single phases?

 

(Bear in mind I'm a light bulb changer and plug wirer, I'm not in the trade!)

21k was in effect to upgrade the supply.   They put in a new 3 phase cable but I don't have 3 phase in my street.  but they still put in a 3 phase cable and connect 2 of the 3 phases -  this is called dual phase.   still 21K   (friend of mine who works for a cable joining company tells me that most of the cost is in effect a "fine" paid to the local council for digging up their road).  Anyway,  thanks for your interest.   plug wiring is also my limit when it comes to electrics!   hehe.  

[RobDorset]

12 hours ago, Mike said:

You could also swap the induction hob for a model that has built-in power management (which shares the power between the rings), if you don't have that already. These use 16 or 20 Amps, rather than the 32A of a regular hob. Of course things won't cook so fast if you have all rings running flat-out.

 

Also consider a load-shedder (such as the Hager 60060), to temporarily cut the supply to a number of selected circuits if the total load approaches the maximum. However you need to be able to shed enough load - the immersion heater and washing machines could be cut without inconvenience, but probably not much else, but that may be enough. You'd need one in each consumer unit that has loads that you wish to shed.

I've got a power management type induction hob but I like your tip about a "load-shedder"   I didn't know these existed.   Thanks....