Hey everyone,
I've got a 7.8 kWp solar setup with a 6 kW inverter that's tied into the grid. Lately, I've noticed that my house's main fuse (rated at 4.4 kW) has blown three times in the last three months, always around peak sunlight, give or take an hour.
I'm wondering if the issue is due to the inverter producing around 6 kW while my household load is low, causing it to feed more than 4.4 kW back into the grid. Should I consider upgrading to a higher power contract? Would I need to go all the way to 6 kW to prevent this problem?
It's a bit confusing, especially since there have been days when solar production peaked, the load was low, and the fuse didn't blow. Any advice would be super helpful!
2 Answers
Yeah, it sounds like your fuse is just doing its job, blowing when there's more load than it can handle. With your inverter pushing 6 kW, you're definitely in overload territory since it's over 136% of what your fuse can take. Sometimes it might blow and sometimes not, depending on numerous factors like how much energy is being used at the moment. If you have a grid meter, check that out because it’ll give you a clearer picture of the import/export.
Also, from a safety standpoint, most places wouldn’t allow a PV system that exceeds the mains input rating. As for whether changing your contract would help, you'd have to talk to your energy provider. Typically, they’ll size the grid feeders to the cable specs, so there’s not much wiggle room there either.
I never knew that it can take longer for the fuse to blow when it's just in overload. Thanks for shedding light on that!
If it’s too costly to upgrade your grid power, you might want to consider increasing your load, or maybe even charge some batteries to balance things out! Alternatively, you could adjust your system setup to limit exports to around 5 kW if that’s an option. It can definitely help mitigate the fuse issue!
I think limiting the exports sounds like a solid plan! I’ll definitely check the inverter settings for that. Thanks!
Thanks, ElectricityGuru88! That makes total sense about the fuse. I found out that I do have a grid meter that tracks all my energy metrics, and I've seen those high export numbers when the fuse blows. I’ll reach out to the installer to see what adjustments can be made.