what ohms trips rcbo's

[daiplayer]

is that because of voltages present on the neutral bar , therefore present on all circiuts connected to the neutral bar . even when off. ? ,,,,,

Sent from my GT-S5830 using Tapatalk

 

[ackbarthestar]

is that because of voltages present on the neutral bar , therefore present on all circiuts connected to the neutral bar . even when off. ? ,,,,,

Sent from my GT-S5830 using Tapatalk

Yep, its the nature of the design of some RCBOs, a sudden surge of voltage on an independent circuit where the neutrals are separated between two dbs causes a momentary unbalance between the earth and neutral.

 

[wattsup]

Thanks guys, some interesting points
i guess some rcbo's / rcd's are more sensitive than others
A bit like people really -;

 

[ColinJones]

Yes, I agree, but that doesn't explain why a non-energized RCD will sometimes trip when another circuit is activated... If you see what I mean

In an ideal world Live and Neutral would follow exactly the same path so that any influence from another circuit would effect both equally. However that's not possible.

It's also not unknown for people to "borrow" a neutral from one circuit to use on another. That can cause the neutral current on circuit 1 not to match the live current on curcuit 1 ..and trip out the RCD.

 

[daiplayer]

In an ideal world Live and Neutral would follow exactly the same path so that any influence from another circuit would effect both equally. However that's not possible.

It's also not unknown for people to "borrow" a neutral from one circuit to use on another. That can cause the neutral current on circuit 1 not to match the live current on curcuit 1 ..and trip out the RCD.

almost garanteed on thw landing light. lol

Sent from my GT-S5830 using Tapatalk

 

[davie spark]

ball park figure:
The actual number is beyond my limited old brain
Insulation res. test n&e would trip (set 500v) rsbo/rcd
What is the threshold / trip ...not trip, ohms reading on tester
I guess some manufacturers may differ slightly, but there must be an inbetweeny?
In the old days, n&e faults were not so important (re-tripping breakers) cos of course no rcd's/rcbo's to worry about...
However, the 'board' would not connect a new supply with a 'low reading' Live Earth or Neutral Earth
Many times low readings were due to damp conditions, new builds. damp plaster etc. Nevertheless the board would not connect until 'their megger' said ok....

The actual figure is 7666.66 ohms but that's at bang on 230 volts, if the voltage was 240 (which it's usually nearer) it would be 8000 ohms as someone else has indicated.