RCD/RCBO where not to use / nuisance tripping

This includes types of overcurrent, Short Circuit and RCD protection
Post Reply
GLion
Posts: 6
Joined: Mon Jul 19, 2021 9:54 am
Has thanked: 2 times
Been thanked: 0

RCD/RCBO where not to use / nuisance tripping

Post by GLion »

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)
AlecK
Posts: 914
Joined: Thu Apr 16, 2020 11:24 am
Answers: 5
Has thanked: 2 times
Been thanked: 352 times

Re: RCD/RCBO where not to use / nuisance tripping

Post by AlecK »

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.
These users thanked the author AlecK for the post (total 2):
GLion (Thu Dec 08, 2022 1:21 pm) • Mazdaman (Thu Dec 08, 2022 9:24 pm)
Rating: 33.33%
GLion
Posts: 6
Joined: Mon Jul 19, 2021 9:54 am
Has thanked: 2 times
Been thanked: 0

Re: RCD/RCBO where not to use / nuisance tripping

Post by GLion »

Thanks AlecK well explained.
Post Reply