Backup generator

[woody1]

The pump is on its own circuit, and I hadn't noticed before that it's only a 6A circuit breaker. It's never tripped but I guess that's because the inrush current (20-30A) is only momentary?

[Dorkeaux]

The pump is on its own circuit, and I hadn't noticed before that it's only a 6A circuit breaker. It's never tripped but I guess that's because the inrush current (20-30A) is only momentary?

Circuit breakers generally trip very quickly on straightforward shorts, more slowly on inrush current.

It depends on not just the amperage rating, but the trip curve rating as well.
Trip curve ratings on domestic circuit breakers are printed on the front of the breaker. They are types B, C or D.

I had to Google the following, You can do it too, Woody1!

Type B: For general lighting/sockets; trips at 3-5 times the rated current (e.g., 30-50A for a 10A breaker).
Type C: For higher inrush, like motors; trips at 5-10 times the rated current (e.g., 50-100A for a 10A breaker).
Type D: For large inductive loads (motors, transformers); trips at 10-14 times the rated current.

[Protagoras]

What's the letter on that 6A circuit breaker (CB)?

I'd guess that it will be a 'B' or a 'C'.

Most domestic CBs will be 'B' curve (trips at 3 to 5 times rated current) and used where surge currents aren't excessive.

For the motor, quite possibly, the CB is 'C' curve (should trip at 5 to 10 times rated current in under 5s).

[woody1]

It's a B6, so just a regular lighting one. I remember many years ago, before LEDs, installing a 1000W halogen outside light but had to swap the bulb for a 750W because it kept tripping.

[woody1]

I've been looking into soft start controllers, and apparently they can be problematic with "capacitor start motors" which is what our pump has.

AI seems to give a good summary of the issues:
https://share.google/aimode/6MtSRsCszefE3F7rx

[woody1]

OFCH uses a bit more electricity than you might expect.

I haven't actually measured it but according to the boiler installation manual, it uses max 140W (burner 90W; circulating pump 50W).

Apart from the borehole pump, the only other big item we'd want to keep running in an extended power cut is the fridge/freezer. I put a plug-in power monitor on it, and was quite surprised it was only 125W. I knew the LCD TV didn't use much but measured it anyway - 45W.