Extending power from garage to log cabin

[Brynmor50]

After being in our latest house for about 6 months, I'm thinking of building a log cabin at the end of our garden about 40-45m back from our garage, but I need to be sure that we can safely and effectively supply it with electricity before even starting the project.

Connecting directly into the main circuit board is not really an option as the flooring and patio needing to come up would be so extensive, I would not start the build until we eventually extend.

There is a secondary consumer unit in the garage which would allow easier access to the garden in order to lay the appropriate cable. Is it possible to feed a third consumer unit from this to the end of the garden, or is this stretching safety in any way?

The main consumer unit has a 100A main switch, then an 80A/30mA RCD supplying, amongst others, the 40A MCB that connects to the garage via a 10mm2 conductor size. The garage consumer unit has a main switch of 40A and multiple MCBs (32A garage socket ring, 32A garden socket ~25m away, 16A socket outside garage, 6A garage lights, 6A garden lights, one spare slot). The majority of this is unused most of the time.

The biggest draw in the log cabin building would be the 7.5A of the treadmill, with minimal low power additions such as led TV, led lighting and usb chargers, WiFi, although I would be interested in what maximum load could be added on top of this.

Thanks in advance.

 

[JohnW2]

.... The main consumer unit has a 100A main switch, then an 80A/30mA RCD supplying, amongst others, the 40A MCB that connects to the garage via a 10mm2 conductor size. The garage consumer unit has a main switch of 40A and multiple MCBs (32A garage socket ring, 32A garden socket ~25m away, 16A socket outside garage, 6A garage lights, 6A garden lights, one spare slot). The majority of this is unused most of the time. .... The biggest draw in the log cabin building would be the 7.5A of the treadmill, with minimal low power additions such as led TV, led lighting and usb chargers, WiFi, although I would be interested in what maximum load could be added on top of this.

It may not be (is not) the ideal but, in view of the practicalities you mention .... if you took a feed from the existing supply to/in garage to the new log cabin, using appropriate cable, you would then obviously theoretically be limited to a total of 40A (per the MCB in your main CU) for everything in both the garage and the log cabin. However, from what you say it sounds as if that would probably be adequate for your needs (at least at present, but not so much 'future-proofing') - and, if that is adequate, I would say that what you suggest would conceptually be do-able.

Kind Regards, John

 

[Trevor SouthWest]

Agreed, though with some lateral thinking you could avoid the issue altogether and use the treadmill to power the other appliances.

 

[JohnW2]

Agreed, though with some lateral thinking you could avoid the issue altogether and use the treadmill to power the other appliances.

I'm a great believer in lateral thinking

It would obviously have to be a non-electrical treadmill (well, one which didn't use electricity), but (quite apart from exhausting you) the 'running costs' could be pretty high ... assuming an (unattainable!) 100% efficiency for everything, to get 1 kWh of electricity would require you to expend 3,600 kJ (aka ~860 kcal) of energy - and, whilst you could buy 1 kWh of electricity for around 16p, I think you would be hard pressed to get anything like 860 kcal worth of food for 16p

Kind Regards, John

 

[Trevor SouthWest]

It would obviously have to be a non-electrical treadmill (well, one which didn't use electricity),

I think it would have to be an electrical treadmill - if you could power it with your own energy it should simply work in reverse and have free electricity coming out! I agree about the energy cost though, just as stupid as these ideas where councils have 'renewable energy' from people's footfall and the like.

 

[JohnW2]

I think it would have to be an electrical treadmill - if you could power it with your own energy it should simply work in reverse and have free electricity coming out!

Hmmmmm. Conventional electrically-powered treadmills are not designed to be used 'backwards'. Even if you could disengage any brake(s) [and engage any clutche(s)], and forgetting about friction etc., I think you might be hard pressed to turn the motor by walking on it, not the least because you would be fighting against a high ratio gear chain. Furthermore, turning a standard AC motor 'by hand' does not necessarily generate electricity (you have to get a magnetic field from somewhere).

I agree about the energy cost though, just as stupid as these ideas where councils have 'renewable energy' from people's footfall and the like.

If I understand you, there is obviously a lot of energy generated by people which is currently 'wasted' (so it would make sense if it could sensibly be 'harnessed') but I'm not so sure about the 'renewable' bit (in the sense that is normally used), since one would effectively be using food as fuel, which may bring 'environmental advantages' into question!

Kind Regards, John