Wiring To A Shed

Hi all,

I wish to install electrics into  my wooden shed ( which is insulated and doubled glazed) to power my Amateur radio equipment, a florescent light and a low wattage heater in the winter, I would be using a 6A and 32A garage/shed CU from Screwfi5

The wooden Shed is located about 5 meters from the rear of my house and has a brick shed in between it and the house, has a concrete path and a patio next to it , so taking any cables underground would be impossible.

My house CU is approx 12-15 meters from the shed near the front of the property, but I have just had my Kitchen rewired which is at the rear of the house and there is some wiring from an old socket and another one for the 30A main for the old cooker point there but both blanked off, both which are still live and wired into the house CU, which is a PME system

My question is could I use the old socket wiring to go into my shed and because I would have to go along the house wall, over the brick shed roof using 20mm conduit would I have to use Armoured cable and if so what size?

right,

getting power to your shed is only half the battle here,

are you going to use electrical seperation? due to your ham kit.

I take it you are aware of a lot of the issues associated with running ham gear outside the EZ [earth Equipotential Zone ] ,

BTW, a LOT of the stuff pushed about of some ham forums regarding this is WRONG and is in fact dangerous and misinformed.

EDIT , you may have a TNCS supply, I would not guarantee it being a PROPER  PME system

Speaking as a radio ham.

I would install a REALLY good TT earth system for your shed and NOT connect it in any way to the earth in the house.

What I'm talking about is a lot of rods, or an earth mat, so your shed electrical earth, and your RF earth for your radio kit are one and the same.

You probably know, but there are some serious potential issues if you link an RF radio earth to a PME earth under certain fault conditions.

Even though you (probably) have no formal training as an electrician, by virtue of your interest in radio stuff you are probably a lot more experienced and know what you are doing than your average DIY electrician.

If the old wiring to the old cooker point still tests okay, then I can see no reason why not to connect to that and feed it to the shack. Use SWA or cable in conduit above ground.  And don't forget to include an RCD in your shed CU.

Didn't know you were a Radio Ham Dave .

Oooohhhhh,

I'll bet Dave is one of them that complains about people like me for using his frequencies without having passed an exam.

Well, he uses our electric and lives in a building without being part P "qualified". 

I'd love to know what that actually means BTW. 

ha ha!!!!!

ProDave said:

Even though you (probably) have no formal training as an electrician, by virtue of your interest in radio stuff you are probably a lot more experienced and know what you are doing than your average DIY electrician.

Click to expand...

you would think that, but form some installs ive seen, they have managed to make it even more dangerous than a normal DIYer would, by thinking they do know better when they dont, and mixing earthing types all over the place and not bothering with RCDs

ProDave said:

Speaking as a radio ham.

I would install a REALLY good TT earth system for your shed and NOT connect it in any way to the earth in the house.

What I'm talking about is a lot of rods, or an earth mat, so your shed electrical earth, and your RF earth for your radio kit are one and the same.

You probably know, but there are some serious potential issues if you link an RF radio earth to a PME earth under certain fault conditions.

Even though you (probably) have no formal training as an electrician, by virtue of your interest in radio stuff you are probably a lot more experienced and know what you are doing than your average DIY electrician.

If the old wiring to the old cooker point still tests okay, then I can see no reason why not to connect to that and feed it to the shack. Use SWA or cable in conduit above ground.  And don't forget to include an RCD in your shed CU.

Click to expand...

Thanks Dave

I will have all my radio equipment earthed as standard, so as long as I earth the wiring in the Shack, sorry Shed with a good few earth rods away from the RF earth I will be ok?

You say I could run SWA or Cable from the old cooker point, could I run 2.5mm twin and earth from the old cooker point wiring or from the old 13A socket wiring to the Consumer unit in the shed/shack, or would it have to be bigger cable like 6mm?

Cheers

Ian

What I was trying to say, was design and install one really good earth mat or multiple rods that will be both the RF and normal earth for the shed.

The cable size you need to calculate given expected loads and length. Since it will supply lighting in the shed as well as power, your target is to limit voltage drop to 3%. Your calculation needs to take into account the resistance of the existing cable from the consumer unit to the old cooker point. Without doing any calculations my gut feeling is 2.5 is too small, and in any case probably under rated when you start using a heater in there in the winter etc.

Sounds to me like 6mm from the old cooker point would be best.

From  my experience, I have found the worst electrical bodges are made by electronics 'engineers' .