Shed power

[Klj1234]

Hi guys am new to this forum

Can someone give me advice on shed power

I am looking at running power supply to a shed which will have a small chest freezer and few sockets for dewalt battery charger I was going to run 2.5mm swa cable straight form house cu (which is rcd protected)
The shed is approximately 40m away

 

[MJPD29]

There are a lot of other factors to take into consideration. What is the installation method for the cable? How much current have you calculated you will need? Is the shed metal or wood and which earthing method is used? And you don't need to have rcd protection on an swa cable with earthed armour but you may require rcd protection on any circuits fed from it.

 

[Spoon]

Welcome to the forum mate.
Also to add to the above, you have to take voltage drop into account. 40 meters is a long distance.
2.5mm SWA cable over 40 meters will give you about 10A before you go over the 3% drop. (Im presuming you will want a light in your shed)

 

[Klj1234]

There are a lot of other factors to take into consideration. What is the installation method for the cable? How much current have you calculated you will need? Is the shed metal or wood and which earthing method is used? And you don't need to have rcd protection on an swa cable with earthed armour but you may require rcd protection on any circuits fed from it.

Method of installation is clipped direct
Current is need small chest freezer and battery charger for dewalt cordless power drill for example
Earthing it will be going back to main CU

My plan is to not have garage board in shed just straight sockets as it is pulled very little current

Both charger and freezer are on a 13amp plug socket

 

[Klj1234]

Welcome to the forum mate.
Also to add to the above, you have to take voltage drop into account. 40 meters is a long distance.
2.5mm SWA cable over 40 meters will give you about 10A before you go over the 3% drop. (Im presuming you will want a light in your shed)

Yes bud that is correct 1 small led light outside door and batten style led in shed its self

 

[Spoon]

Yes bud that is correct 1 small led light outside door and batten style led in shed its self

As it stands at the moment you are looking at a supply of just under 10A for a 2.5mm SWA cable at 40 meters.
That's not enough for your stuff.
Also this work falls under Part P and is notifiable.
Might be good to get an electrician in to do it. Or for you to help out and save some money.
There is a great guy who lives your way. @telectrix . I got him round when I had issues with a lighting circuit.

 

[Klj1234]

As it stands at the moment you are looking at a supply of just under 10A for a 2.5mm SWA cable at 40 meters.
That's not enough for your stuff.
Also this work falls under Part P and is notifiable.
Might be good to get an electrician in to do it. Or for you to help out and save some money.
There is a great guy who lives your way. @telectrix . I got him round when I had issues with a lighting circuit.

I am a trainee electrician but am struggling to find the right information for this subject

 

[Dustydazzler]

If you actually measured the VD on 40m of 2.5 i would be surprised if it was much at all , certainly not 7 or 8 volts

But I suspect if you design the circuit using the OSG tabulated values it will suggest 4mm cable

 

[littlespark]

If you’re running a new circuit out there, future proof it….

will you ever be using a lawnmower, leaf blower etc out there?

hottub? Has been known.

garden bar?

4mm minimum, gives some extra scope. Not a problem if your coming from CU.

 

[Klj1234]

If you’re running a new circuit out there, future proof it….

will you ever be using a lawnmower, leaf blower etc out there?

hottub? Has been known.

garden bar?

4mm minimum, gives some extra scope. Not a problem if your coming from CU.

Hot tub is going on separate circuit this circuit is solely for shed to run a small chest freezer and odd bit of power for battery charger

 

[telectrix]

question is what earthing system, and is the shed liable to have any exreaneous parts e.g. a water supply run in condictive pipework. this would entail using a larger cable if PME/TNC-S.

 

[Klj1234]

If you’re running a new circuit out there, future proof it….

will you ever be using a lawnmower, leaf blower etc out there?

hottub? Has been known.

garden bar?

4mm minimum, gives some extra scope. Not a problem if your coming from CU.

question is what earthing system, and is the shed liable to have any exreaneous parts e.g. a water supply run in condictive pipework. this would entail using a larger cable if PME/TNC-S.

Earthing is tns system at main CU

No water supply in shed its a shed not a summerhouse the freezer is for falconry food

 

[Klj1234]

Right guys I have priced up both methods of installation straight form main CU and adding additional CU( garage board)in the shed and running lights and sockets off that

I think I will be adding additional CU in shed feeded by 10mm swa 2 core by my calculations the 10mm is more that capable of handling the current needed

 

[Dustydazzler]

How did you come up with 10mm 2c

If you take a design current of 20a you won’t need 10mm

you are just wasting your money

 

[Pete999]

Right guys I have priced up both methods of installation straight form main CU and adding additional CU( garage board)in the shed and running lights and sockets off that

I think I will be adding additional CU in shed feeded by 10mm swa 2 core by my calculations the 10mm is more that capable of handling the current needed

Show us your calculations then, you may get more help that way.

 

[telectrix]

10mm does seem like overkill. 6.0mm willl handle 45A, VD permitting.

 

[Klj1234]

10mm does seem like overkill. 6.0mm willl handle 45A, VD permitting.

It's the run of 40m with bends and turns I calculate for 50m just incase

 

[telectrix]

so at 40A on 6mm at 50m you VD would be (7.8 x 40 x 50) = 15600mV or 15.6V. but will you need 40A (cannabis farm?)?

30A would be 11.7V - .sensible if you have LED lighting.

 

[Klj1234]

so at 40A on 6mm at 50m you VD would be (7.8 x 40 x 50) = 15600mV or 15.6V. but will you need 40A (cannabis farm?)?

30A would be 11.7V - .sensible if you have LED lighting

so at 40A on 6mm at 50m you VD would be (7.8 x 40 x 50) = 15600mV or 15.6V. but will you need 40A (cannabis farm?)?

30A would be 11.7V - .sensible if you have LED lighting.

As stated its is for a a small chest freezer and the odd charger for drills ect
1 outdoor light and 1 batten style light I have answered the questions over and over

The 40A I measured up for was for over estimate in case later years I need anything else

I can not give any more information than what I already have

please only reply If its related not childish comments like above statement

 

[telectrix]

wonder what is childish about doing a volt drop calc.for you. also wonder if Amazon sell a sense of humour.

 

[Klj1234]

wonder what is childish about doing a volt drop calc.for you. also wonder if Amazon sell a sense of humour.

Cannabis farm I was referring to bud

 

[DPG]

Cannabis farm I was referring to bud

There's a joke in there but I'll leave it I think based on recent posts in the thread

And I think Tel doing the calculations deserves a thanks personally.

 

[littlespark]

Cannabis farm in a shed would be easy to find by local plod and a heat sensitive camera.
Same goes for normally cold roof space.

I think we were all a little surprised that you jumped 3 cable sizes after your first thoughts.

TBH, 2.5mm will probably be fine if it’s just a freezer, chargers and a couple of lights ONLY. Nothing else.

 

[Klj1234]

Cannabis farm in a shed would be easy to find by local plod and a heat sensitive camera.
Same goes for normally cold roof space.

I think we were all a little surprised that you jumped 3 cable sizes after your first thoughts.

TBH, 2.5mm will probably be fine if it’s just a freezer, chargers and a couple of lights ONLY. Nothing else.

It was just the long run i was worried about with the 2.5mm

As for the cable jump

the original idea was a radial circuit coming form my CU in the house plus I totally different radial for hot tub so two different circuits both in 2.5mm
( I haven't done cals for hot tub yet)

Or

The cable jump (10mm) was to power a brand new CU in shed its self then form that board ( shed ) I would power the hot tub heat and shed

Thank you kevin