Can 110Vac RCD (ELCB) be used on 230Vac system?

[digitrex]

I ask this question because we are using European voltage in our country but America made diesel engine driven generator having 50Hz 2x110Vac source is very common here.

According to the manual, the 2x110Vac supply source can be connected in series to give 1x220Vac single-phase output with the winding centre-tapped earthed.

However, when we apply 230Vac RCD on this power source, the tripping time is longer than specified because the voltage to ground is only 110V. I am thinking of using 110V RCD but then I am encountering the voltage rating violation.

Do you think the insulation level of 2-pole 110Vac RCD can be safely used under the 220Vac system or is there other alternative?

 

[rbulsara]

Simple answer is no for a 2-pole, imho.

More so legally than technically. Even if it malfucntions for reasons other than the voltage rating, you will still be liable. It is important that we technocrats also become good business persons, not all decision have to be based solely on 'engineering' or technical theories.

Why can you not get 230V RDC? How expensive can it be?

 

[ruggedscot]

You could get it to work but it would be pretty expensive as you would need to put in a transformer 1:1 between the gennerator and the circuit that you are supplying...

If you did this you could then generate a 220v circuit with the neutral grounded giving 220v without this centre tap thing. RCD's are designed for single phase and neutral earthed circuits, you are trying to run one through a split two phase circuit and this will cause you problems due to the split. Remember that these RCD's are rated at generally 30mA.

Rugged

 

[ScottyUK]

Thinking aloud, you could possibly use a three-pole RCD. Switching devices aren't permitted in the neutral unless ganged (in the UK), so this arrangement should be ok if you switch both poles and the neutral together.

Tripping time of a current-operated RCD is determined by leakage current as the name implies. The circuit voltage doesn't matter, other than the built-in test button may give incorrect results because it connects a resistor line-neutral and would therefore pass less current at the lower voltage. An RCD tester may well have the same problem.



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