I found a b-type breaker. (
Amazon.com - https://a.co/d/b9rCIgi) Is this one correct?
But I'm puzzled. Will it trip at 13.5A (10 x 135%) or 20-30A (2 to 3 times rating)? Or is it somehow both, each under a different condition?
Thanks,
Andrew
Hi Andrew
That's for DC solar panels, not AC. It's 16A not 10, and it shows type C on the front. You only need a single pole one.
These circuit breakers contain two mechanisms to trip them.
There is a thermal trip that is basically a bimetallic strip warmed by the current passing through, so when that gets to 135% of the rated current, it trips the breaker. But the characteristic is a slow response, as the heating takes seconds or minutes depending on the amount of overload. So that stops cables melting etc. under sustained slight overload.
Then there is also a magnetic trip like a solenoid, where, when the current is bigger (that's the 3 to 5 times overload), the electromagnetic field is strong enough to trip the switch, which it does in milliseconds. That's to stop a big bang or fire when there's a short circuit.
I guess the ideal for protection of the Jackery would be a 10A fuse, but carrying round a box of those, and fiddling around replacing them would be a pain, so a breaker is the next best thing. But it comes with compromises. Electronic components have got more robust during my lifetime, but they are generally not good at handling transient overloads, so the Jackery may be vulnerable to overload. It depends on how robust their overload protection is, and whether your installation might create any transient spikes on being connected or disconnected. Fundamentally you have an inverter that is underpowered for the potential load it might encounter. I know you don't ever intend to overload it, but potentially there is that possibility. If there wasn't, I wouldn't be suggesting the breaker, but even with it, there is always the possibility of failure.
Personally I would be buying the breaker from a reputable electrical distributor in the US, not necessarily from Amazon.
Just been having a look on Amazon, and I see the problem finding a B curve breaker. You need something like this (but available!) sorry - link doesn't work, so posted pic below instead!
And sorry to sound a bit blunt, but please do your own research. This forum is not supposed to give step-by-step guidance, and I don't want to get too close to that scenario I'm afraid.