Generator and boiler lockout revisited

Feb 16, 2007 2 Replies

Hi Thanks to those who replied to my posting on this a few weeks ago in which I said that ch boiler locks out when I run it from a petrol generator supply



Sparks: you suggested I measure voltages as generators are often centre tapped. Results (no load) are - L--N 240v N--E 85v L--E 85v



I am now more puzzled than ever. Where's my missing 85v?


-- Richard


The output is probably floating - with no electrical connection to earth - and what you're measuring is probably just an induced voltage. Chances are that you can actually strap N to E with no ill effects.

Try this: Connect a mains 100w bulb between N&E and see whether it glows at all. Assuming it doesn't (mine didn't!), repeat the above 3 measurements with the bulb in circuit. You'll likely get something very close to: L--N 240v N--E 0v L--E 240v

If this is the case, you can safely strap N to E with something having a much lower impedance than a lightbulb. My genny has 2 x 13A sockets. I have made up a plug which has an internal wire between N and E, and that is plugged into one of the sockets - with the other socket being used for the real output. The genny runs perfectly happily. I haven't yet tried powering my boiler with it (preferring to wait for warmer weather, when the boiler is less critical) but I have every confidence that it will work.

Agreed, My generator has the E and N bonded together, so I get

E-N - 0 L-N - 230 L-E - 230

I have also installed a Briggs&Stratton transfer switch in the house. (This has a 30mA RCD in it.

Before I installed the generator, we have a fair few power cuts. Afterwards, we have had two short ones in 3 years, and these were both on the same day, about 2 weeks ago!!! Bloody typical isn't it!

Sparks...

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