Circuit Breaker

[grizzly bear]

My microwave malfunctioned last night and the circuit breaker duly tripped and turned off everything lights and plugs , downstairs and upstairs. On looking I saw the big switch has gone down. I turned it back up, checked which plug had caused it and everything duly went off when the microwave was plugged in BUT not the kitchen light. Is it on a different circuit if so how does the big switch not kill the power to the kitchen light and if so what does, should the light in the kitchen be faulty? Thanks for any help.

[johnny.5]

it could be that the lights are on a diferent circuit to the sockets

[weecalf]

The trip switch should put everything off I would have thought .Thanks also for proper use of the term “circuit breaker” as all these snazzy terms get used for you know what .

[mibn2cweus]

Possibly kitchen light has battery backup so all isn't dark in event of power failure. Well, would be nice anyway.

[malagabob]

Lighting circuits are and should be on a different circuit to power (plug outlets) Also cooker power and electric showers/Immersion heaters should be on their own circuits.

[KARL]

When you say "big switch", do you mean the master/supply switch or is there a residual current device/"earth leak" breaker in your consumer unit ? If the latter is there then it may well not govern lights nut instead only the heavier circuits in the house.

[KARL]

The RCD can be recognised by a "Test" button being present.

[The Builder]

One of two possibilities, Grizzly.
You may have a "split load" consumer unit. i.e. TWO RCDs (one for each bank.)
Some circuits on one bank, and the rest on the other. These RCDs will act independently.

OR... your system may be a few years old. Today, everything is protected by RCD (except for certain situations which I don't need to go into.)
A few years ago, it was common to put sockets for instance on an RCD protected bank with a "split load" arrangement, but have lighting circuits on the other (unprotected) bank.

The idea was that most "mishaps" occur with sockets, thus tripping the RCD. In that event, the lights stayed on to avoid having to scratch around in the dark.
The modern set-up is far safer.