Which 110v Transformer do you need on UK building sites

How to choose the right transformer, 110v extension leads & junction boxes

In the UK you need a 110v transformer powered tools because the only corded power tools you can use on the building site are 110 volt as well (battery tools are all OK).

110 volt power is far less likely to cause a fatal electric shock than 240v if you have an accident or a cable is caught/cut/gets wet accidentally for any reason.

I'm not sure the same rules apply to kitchen fitters though because most of the ones I meet use 240v tools!! 

Which 110V Transformer to use on the building site

The transformer plugs straight into the 240v mains socket and reduces/steps the power down to 110v. There are a couple of factors that will affect which transformer is best for you.

I've always bought 110v power tools because even though I have to carry around a heavy transformer I know I'm not going to get turned away from a job by the site agent for health and safety reasons.

I use a twin socket transformer which is plenty powerful enough for the carpentry 110v power tools I use.

Power rating

110v Transformers are available in lots of shapes and sizes, with varying amp outputs and with one, two or more tool sockets. If you are only going to use the transformer yourself for things like a mitre saw, Hammer-Drill, planer, jigsaw and other normal 110v power tools then this 3KVA 110V Transformer like mine will be more than sufficient for you too.

As long as the power rating (amps) on your tools doesn't exceed the one on the transformer you'll be OK.

110v transformer accessories

You can't run a 240v lead from the power socket to your workplace and then plug the transformer in there as the lead still poses a risk to others. So, to go with your 110v transformer you'll want a few 110v accessories as well.

I have an 110v extension lead and a four way junction box too so I'm not plugging/unplugging tools all day.

I don't worry about plugging 2,3,4 or more power tools into it because I can only use 1 tool at a time, I won't overload it.

If a few people will be working it is better to have two transformers than overload a single one.

If you are on a large site though it is likely there will be a large generator for every one to get their 110v power directly from.

General safety points

  • It's pretty much a case of plug in and go but read the manufacturers guidelines each will vary
  • Some have a trip button to cut the power if there's a problem. If yours isn't working try that before you take it back to the shop 
  • Leave the transformer close to the ground. They're pretty heavy (around 25kg) and you don't want it to fall on you or anyone else. Even if it landed on your foot, it would break it. Don't put it on a worktop, chair or anything weak that might break under the pressure. Get a 110v extension lead and leave the transformer somewhere safe
  • Don't let it get wet. I've used mine outside in the rain but kept it off the wet ground and covered it with a wheel barrow. If it gets wet it could cause a shock

Have a question or comment about choosing 110v transformers?