electricalforum.nz

Hi,

I'm going setting up a new install of the following. I'd prefer to have RCBO's on everything. I've run air compressors, skill saws and saw benches at home through an RCD and I've never had any nuisance tripping. But I've heard people talk about it.

Anyone see any issues with RCD/RCBO on the following:
- Sceptic tank, less than 1kw, has 80w blower and a 550w pump
- Standard residential kitchen oven
- Water pump 750w (Plugged into socket anyway)
- Burglar Alarm
- Gas water heater (Plugged into socket anyway)

You should have no problem with any of those.

so-called 'nuisance tripping" is almost always caused by poor selection and / or installation;
especially standing leakage; including
- capacitance of cables
- having too many appliances on same RCD (especially switch-mode power supplies).

When RCDs first became common, it was recommended not to use them on freezers .
But that wasn't because refrigeration systems cause tripping, it was to avoid the contents thawing if tripped.
Which was faulty logic; because if it trips there's a bigger problem than food thawing.

30 mA RCDs must not trip below 15 mA (typically they operate at around 25 mA.)
Any appliance with that much leakage is faulty to the point of being unsafe.
This includes water heaters, stoves / hobs, or anything else.

Minimum IR for an appliance with elements is 10 k ohm - which will give 23 mA.

Currently in Oz, RCDs are required for all final subcircuits in residential.

Thanks AlecK well explained.