Workshop advice needed

Postby Rich.h » Tue Aug 28, 2012 4:33 pm

Hoping someone can offer some advice for me, I'm converting my back yard into a workshop (mostly woodwork). and I'm not 100% about how to do the electrics. To give an idea of how things are at this time, I have oil heating for the house and there is an existing double socket outside which currently feeds the oil burner. I believe this is spured off the back of an internal double socket and part of the main socket circuit for the house. The sockets are all one one circuit and my fuse box is of the older style using ceramic and wire fuses rather than trip switches.

All of the equipment I plan to use in the workshop will be 240v and the most hungry being the tablesaw. Apart from a strip light, battery chargers and perhaps a radio, there will never be more than one appliance running at any one time.

So my question is, am I safe to simply take a new spur off the external socket already in place or will I have to run a whole new cable back to the fuse box? If a new cable is needed will I have to overhaul the entire system as I can't see anyway to tie it into the existing system.
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Simply Build It

Postby ericmark » Tue Aug 28, 2012 9:37 pm

New items must comply with new regulations but old item may remain as they were.
So likely a RCD FCU will be required to supply any new items. Once you go over 13A the cost sores but up to 13A a RCD FCU will normally mean all after it will comply.

If from a 32A supply then only one spur is allowed from any socket on the ring or a FCU. Once it supplies a FCU after that you can have as many sockets as you like.

With 20A and less supplies the rules a different. Although all new sockets (under 20A) must be RCD protected.

There are two basic RCD's active and passive. Where under fault conditions the voltage may drop to a point where the RCD voltage becomes too low for the electronics to work we use an active RCD. This means any power failure and you need to reset the RCD.

Where the RCD is close to the consumer unit then we can use a passive. These do not trip with a power failure. In the main we work out which type by measuring the earth loop and line neutral loop impedance. If you can't measure it then use an active type and play safe.
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