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Plug in RCD 230V or 110V transformer

Former Community Member
Former Community Member
I'm curious to see what peoples opinions are on the two different options available for safer power tool use either using 110V tools with a site transformer alone or 230V tools however using these with the plug in RCD. 


I'm aware of the center tapped site transformer splitting the voltage into 55V so there is the arguement that it's only 55V pushing through your body, vs the RCD option, you're exposed to the potentially full 230V but the RCD cuts the supply almost instantly. However this is based on the RCD actually working and detecting a fault and even if it does perhaps even that brief exposure to 230V may be enough for some people to be fatal. Then again 55V maybe enough for some people too to be fatal. 


Thought?


  • 0
    What amazed me in many cases on site, was the use of a very long 240 Volt extension lead to a 110 Volt yellow box transformer, the 240 Volt lead running  over piles of bricks, across an access route for vehicles, through puddles and having been buried by a pile of sand, then a drill was plugged into the yellow box at the remote end.


    Z.
  • 0
    Rubia30:

    Well thanks for the responses, seems that the transformer is the way to go over the RCD. Most of my power tools are corded at 110V. I do like the battery tools but still don't think they are quite there yet compared to battery tools for the bigger consumers such as mitre saws and circular saw. I've literally watched people with the Dewalt flexvolt system get no more than 12 cuts in sheets of ply before the battery is done. Given my work it is easy in most situations to set up my 3.3KVA transformer outside or in a customers garage and if necessary run a 110V extension, though I rarely have to most of my tools have long enough leads on them. The 0.75KVA will be kept closer to power the smaller tools such as the multitool etc. Again I have seen the battery equivalents die after just 20mins of use. 


    The reason for asking the above question is that it looks like I'll have to buy a bigger transformer for the intended 2100W router, the 3.3KVA transformer only has 2 16Amp sockets so I need a new one with a 32Amp socket and may as well get a 5.0KVA so can run the router for more than 5-8mins. The router will be the only tool I have that will require the bigger transformer, all my other tools are at or below the continuous rating of the 3.3KVA transformer. That's why I was wondering for just one tool which will not be used on site ever, maybe rarely on a job, but mainly for home projects a 230V tool would suffice.    


    just bear in mind that you cant carry a 5kW transformer on your own...


  • 0
    I have seem quite a few 110v systems in engineering workshops and other factory settings where someone has acquired a 110v transformer, no centre tap, run it through a single-phase distribution board with single pole devices to a network of yellow sockets. CPC comes along for the ride.
  • 0
    I think it`s a horses for courses type thingy.

    Depends upon the amount of use and what mitigations are in place or easy to do.

    There is no one answer for all situations.

    All that aside purely for theoretical (electrical only) safety considerations we should be asking some "starter for ten" type questions.

    How easy is it to produce a potentially harmful fault and what mitigation (probability of adequate mitigation) will either system achieve?

    RLV gives us a shock hazard between live conductors of 110V and 55V (63V) live to earth hazard.

    RCD gives us a quick disconnection which might have a up to 7% failure rate and a 95% theoretical success (life saving) outcome of the L to E fault on the 93% of those correctly functioning  RCDs .


    Obviously batteries, at first glance, appear a safer option, but do have some potential dangers to consider too - they are not totally foolproof.


    I have a suspicion that, amongst UK electrics trades, RLV might well win in a poll (for power tools) even before BOFDs mentioned 55V is really 45V explaination

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