Thread: Another power to the shed question!

Hi Gareth,
that option would be ok in the short term, I've got a similar set up to get power down to the saw bench in my (fire) wood shed. But I only use that once or twice a year.
How many years do you intend using this arrangement and how frequently?
In the long term I could see this becoming an absolute pain in the butt.
How about posting some photos or a diagram of your situation, it's only 30 metres and you might be surprised at the amount of expertese out here.
Regards,
Geoff.

I agree with Geoff, post a photo of your situation. For example it is sometimes possible to place conduit down the sides of concrete stairs or go overhead (it might still not be legal but it will be safer).

As a kid in the 1960's I used to drag a cable down to the shed. Ones intentions are of course initially safety focussed but I began to forget and would often leave it for weeks without dragging it back to the house. After a couple of years or so of weekend warrior use the cable had become so twisted and damaged I had to throw it away. Mum dropping a pot plant on it where it crossed a wooden footpath did not help. My eventual solution was to suspend a new cable on wire run between the house and the shed roofs. My uncle who worked for the SEC at the time gave it the once over to make sure it was not going to cause a problem.

Admittedly the extension cables of today are better than those from the 1960s but one problem with your solution is you are placing two extra power points in line with every appliance and this places extra resistance in the line. This means the voltage drops and so appliances will pull more current. Initially this will be small but will increase as the powerpoints and line age.

Legally of course if things go pear shaped then it will be hard to defend. You won't be able to use the caravan defence because a shed is not caravan.

Thanks Geoff,

How many years i put up with it depends on whether i ever tackle the task of getting past those stairs! I do plan to spend quite alot of time in the shed so i think you be right, wont be long for that cord gets pretty annoying to have to use.

I've posted up some pictures that i had on my phone. You can get a good idea about the stairs form one of them. They wrap around the bottom of the house and continue. So any conduit would somehoe need to get underneath at the bottom or at teh top and then run alongside. The shed is strait down 30m to the bottom of the yard.

Cheers,

Its a bit hard to see what is going on in your photo as it is so small but I would consider putting a beam at 2.4m high over the stairs and and a post at the base of the stairs and then run the cable along the beam and down the post. If you put it all inside conduit it should be safe.

Originally Posted by BobL

one problem with your solution is you are placing two extra power points in line with every appliance and this places extra resistance in the line. This means the voltage drops and so appliances will pull more current. Initially this will be small but will increase as the powerpoints and line age..

Thanks for the reply Bob, i'll get some better photos to post up.

In regards to the voltage drop, this would be an issue regardless of whether i use an extention cord or not i assume? Is there a way to get around this? I;ve heard this can damage the power tools.

Voltage drop is overcome by using larger cable. Give your local sparky a call. He will be able to advise you on the best route to run the cable as well as determine what size cable you need. Installing it in conduit on the surface and using a catenary wire are both valid and legal options. Cable can be run through the roof to the closest point to the shed and then via overhead, suspended on a catenary, to an anchor point on the shed.

Might have to bight the bullet and dig up some stairs.Perhaps i can run conduit over one of thestairs and brick over that. The other half will not like suspended wire running down to the shed. Already doesnt like the shed now right in the middle of her view from the windows

I'm not experienced but i think 2.5mm cable over 30m drawing 15amp only has a voltage drop of about 2V. So may not really be an issue. Could always upgrade to 4mm cable, But i already have a 100m roll of 2.5 so would like to try and use that up if going the hardwired route!

Whilst I can't get anything from your photo, you still might be able to dig under the stairs. There are tools available to dig tunnels under just about anything. Have seen the gas authority dig right under a road for one small pipe. See if you can hire something.

One trick, that depends heavily on the sub-soil type - and whether you have adequate drainage - is to get a length of electrical conduit slightly longer than your stairs are wide.

Drive it horizontally into the soil under the stairs, then slip a garden hose inside... and turn it on. Keep wiggling and twisting the conduit until you've worked it into the soil for as much of it's length as you can. (A pair of vice-grips clipped on the free end as a handle can make life far easier, too!)

Then you can dig a trench down on t'other side of the stairs to locate the far end of the conduit.

It can be messy, but it can also save a lot of time and expense when conditions are right.

Sadly, it can also be frustrating as all hell when you've worked it 3/4 of it's length in only to have it stop dead... because some mongrel brickie threw building rubble underneath the stairs.

Originally Posted by g-money

I'm not experienced but i think 2.5mm cable over 30m drawing 15amp only has a voltage drop of about 2V. So may not really be an issue.

Actually it's just under 8V. (7.965V)

Originally Posted by NCArcher

Actually it's just under 8V. (7.965V)

Well, i was way off then!

That would still be within the 'acceptable' 5% range then i guess. For now until it deteriates. It should atleast do until i can work out and afford to have a 4mm line run strait from the mains to the shed. I suppose you can test with a multimetre to check if the drop is getting worse. How much of a risk would this actually pose to the tools being used? Only one of them is 15A it only really gets occational use.

Might also try the conduit and hose suggestion, thanks for that

Thanks for all the great help so far guys. Really looking forward to getting this shed finished. Have only put down the floor so far.

Have a more detailed chat with your sparky. In the States, direct burial is legal, with proper grade of cable, depth, and junction boxes. Might also be advisable to place a metallic warning tape above it but underground.

Extension cords get very old very fast, especially with outdoor plugs.

Cheers,
Joe

In these days of rising electricity costs, there is always the option of a generator

I frequently use a generator when out at my mate's farm, particularly for welding, and have used power tools easily. Have been using generators for years with the caravan, sometimes drawing up to 30 amps with 3 appliances on at the same time.

Just a thought

I have had a couple of past experiences running high drain tools on extension leads that may or may not give you some insight.
The first was an existing wired shed we had on 20 acres a while back. It was already wired for power when we bought it. For the entire time we were there we had annoying hiccups in that shed. If my 15 CFM compressor tried to start up at the same time as my TS was running, it would cycle badly. Try to start, stop, try again and stop etc. I'd have to quickly turn my TS off until it finished. I bought a new Gasless mig and it was great for very fine small tacks which is what I bought it for but it was impossible to actually run a continuous bead. I just put it down to my inexperience with mig and used my stick welder.
Just before we sold the property I had to dig a small drainage channel and uncovered the supply line. It was 2.5mm extension cord in conduit just 3" below ground. Total run was about 20 mtrs.
Most of my machinery has been in storage since we sold but I have concerns about what damage may have occurred during our time there. In particular, my compressor. It will be the first item to go get checked out.
That same gasless mig works just fine in my new shed with proper wiring.

The second instance was when I was building. I had a tradesman trailer with the same compressor mounted to it. I wanted the longest possible run from a power point to my nail gun. I spoke to a friendly sparky and he consulted a fairly extensive looking chart for me and calculated what the longest run of extension cord I could run on a worse case scenario before experiencing significant power drop. From memory it was around the 25 to 30 mtr mark. I then hardwired that length of lead into the trailer and bought enough air line to go the rest of the distance. Worked a treat because I got someone involved who understood these things and followed his guidelines.

So, two experiences with long runs of extension lead. One good, one bad.

ETA: Just remembered something else. That same sparky told me to never run the trailer compressor with the lead coiled up if I could park near a power point. Too much heat build up, which I had had previous experience with in my first mentor's cabinet shop. A coiled extension lead running a shaper set fire to a pile of sawdust it was laying under. We caught it in time but could have been nasty.