Fox ESS Error Code-1 No Utility, Error Code-26 Grid Voltage Fault, Error Code-27 Grid Frequency

[Will]

Error Code:
Error Code-1 No Utility
Error Code-26 Grid Voltage Fault
Error Code-27 Grid Frequency

I'm making this post to help other owners searching for this error message understand the problem and how to resolve it.

Issue:
These three errors above normally appear together because the grid power connection to the inverter has been isolated. I.e No power to the inverter.

Solution:
This is normally because your circuit breaker has normally tripped to an off state. Locate your circuit breaker or trip switches and try to reset it to restore power.

Circuit breakers should not trip, there is normally a problem or fault or the more commonly, the circuit breaker itself is undersized and tripping during high load situations like force charging.

As a general rule inverters should be installed on the following MCB size:
3.7kW inverters - 20A MCB
5kW inverters - 32A MCB
6kW inverters - 32A MCB
7kW Inverters - 32A MCB
8,9,10kW Inverters - 64A MCB

[Pagglukia]

Thanks Will for this very timely post

I experienced this on Sunday in pouring rain during storm Bert The breaker tripped and I reset, but it tripped again a few minutes later. After retetting for the second time (after the force charge session) it has been been fine ever since. I initially thought it may have been caused by a surge related to the storm but aftyer reading your post I remember that at the time I was force charging (programmed to take advantage of a free power session from Octopus) so possibly this was the trigger?

I have a recently installed 3.6k FoxH1 inverter, 11 440w CS panels and a Fox ESS 5kw battery with a B20 breaker.

This has happened once before, not during a charge event

Any thoughts?

Anthony

[graham]

I've just found I had the same problem. The error log gave this, Tuesday, morning as the time, but looking at history, we've had no function since 19:27 on Sunday 1-12-24.
I've reset it - I'm not sure that it took the first time, so I did it twice, and now we are charging, etc. I hope this is a one-off, but I am worried.

I'm looking at what was going on when the system went down, but I can't see anything untoward in the power consumptions, etc. - it wasn't charging at all, and we were drawing about 800W from the battery at 23% charge.

I've also looked at RVolt, and I don't see any obvious spikes, though I don't really know what would be good or bad voltage wise.

Graham

[graham]

duplicate?

[Dave Foster]

I've just found I had the same problem. The error log gave this, Tuesday, morning as the time, but looking at history, we've had no function since 19:27 on Sunday 1-12-24.
I've reset it - I'm not sure that it took the first time, so I did it twice, and now we are charging, etc. I hope this is a one-off, but I am worried.

I'm looking at what was going on when the system went down, but I can't see anything untoward in the power consumptions, etc. - it wasn't charging at all, and we were drawing about 800W from the battery at 23% charge.

I've also looked at RVolt, and I don't see any obvious spikes, though I don't really know what would be good or bad voltage wise.

Graham

If your breaker tripped is it an MCB or an RCD that tripped - If it was an MCB what is it's rating?, it may be too small. If it was an RCD that tripped it is likely it is rated at 30mA - Fox suggest that an RCD with a trip limit of 100mA is used, you often 'get away' without having to do this but if your have a large house or lots of large appliances with heaters your overall leakage current is higher and the inverter may take it over the limit - probably best to discuss this with your installer/electrician.

[graham]

I've just found I had the same problem. The error log gave this, Tuesday, morning as the time, but looking at history, we've had no function since 19:27 on Sunday 1-12-24.
I've reset it - I'm not sure that it took the first time, so I did it twice, and now we are charging, etc. I hope this is a one-off, but I am worried.

I'm looking at what was going on when the system went down, but I can't see anything untoward in the power consumptions, etc. - it wasn't charging at all, and we were drawing about 800W from the battery at 23% charge.

I've also looked at RVolt, and I don't see any obvious spikes, though I don't really know what would be good or bad voltage wise.

Graham

If your breaker tripped is it an MCB or an RCD that tripped - If it was an MCB what is it's rating?, it may be too small. If it was an RCD that tripped it is likely it is rated at 30mA - Fox suggest that an RCD with a trip limit of 100mA is used, you often 'get away' without having to do this but if your have a large house or lots of large appliances with heaters your overall leakage current is higher and the inverter may take it over the limit - probably best to discuss this with your installer/electrician.

It's a LIVE CA132b, 32A circuit breaker, which had tripped. That should be good to 7.6kW at 240V, where the system reports itself at drawing and giving upto 5kW. Should I be concerned the headroom is a bit small? I usually go for a factor of 2, e, or Pi, rather than root 2, for mundane systems. But we weren't drawing anything like 5kW from the inverter when it dropped out. It's coupled to a LIVE RDA263-100, 100mA RCD and an OB112, which reads 1552067 kWh (is that, roughly, 1230kWh per day in 21 months?).

I hope that's enough information, as I had to move the vacuum cleaner to get it, and I prefer it if that just sits there gathering dust.

Would it possibly have tripped for a dip in supply voltage?

This is the first time I've had to reset that, or had an issue anything like this, in the 21 months the system has been up and running. As said, we weren't doing anything unusual at the time - dinner was late that day, so the fan oven was on, but not heating, as were the heaters for the two reptile cages (which are different from the kids bedrooms), and that's the same as some point in nearly every day since installation.

I know MCBs can go funny when they're very old - I've replaced two of the ones in the house box for being over sensitive in the 20 years we've been here. But they certainly weren't new when we moved in.

I guess I'll just have to watch this one, and see if it goes again soon. If it does turn out to be a frequent problem, I suppose I'll have to replace it. That may mean learning how to isolate it from both mains (easy) and the inverter (not so sure). But it's at least tomorrow's problem, I hope.

Graham

[Dave Foster]

It's a LIVE CA132b, 32A circuit breaker, which had tripped. That should be good to 7.6kW at 240V, where the system reports itself at drawing and giving upto 5kW. Should I be concerned the headroom is a bit small? I usually go for a factor of 2, e, or Pi, rather than root 2, for mundane systems. But we weren't drawing anything like 5kW from the inverter when it dropped out. It's coupled to a LIVE RDA263-100, 100mA RCD and an OB112, which reads 1552067 kWh (is that, roughly, 1230kWh per day in 21 months?).

I hope that's enough information, as I had to move the vacuum cleaner to get it, and I prefer it if that just sits there gathering dust.

Would it possibly have tripped for a dip in supply voltage?

This is the first time I've had to reset that, or had an issue anything like this, in the 21 months the system has been up and running. As said, we weren't doing anything unusual at the time - dinner was late that day, so the fan oven was on, but not heating, as were the heaters for the two reptile cages (which are different from the kids bedrooms), and that's the same as some point in nearly every day since installation.

I know MCBs can go funny when they're very old - I've replaced two of the ones in the house box for being over sensitive in the 20 years we've been here. But they certainly weren't new when we moved in.

I guess I'll just have to watch this one, and see if it goes again soon. If it does turn out to be a frequent problem, I suppose I'll have to replace it. That may mean learning how to isolate it from both mains (easy) and the inverter (not so sure). But it's at least tomorrow's problem, I hope.

Graham

A 32A breaker should be more than sufficient for a 5kw inverter unless you wire the EPS to run in bypass, but as you say there was no particular load on the system at the time so unlikely to be over current. The 100mA RCD should also be more than enough to cope with the transients - it could as you say be a problem on the grid side that has caused the breaker to trip, but also worth double checking that all the terminal connections are tight (i've seen problems with OB112 terminations being loose and arcing).

[graham]

It's a LIVE CA132b, 32A circuit breaker, which had tripped. That should be good to 7.6kW at 240V, where the system reports itself at drawing and giving upto 5kW. Should I be concerned the headroom is a bit small? I usually go for a factor of 2, e, or Pi, rather than root 2, for mundane systems. But we weren't drawing anything like 5kW from the inverter when it dropped out. It's coupled to a LIVE RDA263-100, 100mA RCD and an OB112, which reads 1552067 kWh (is that, roughly, 1230kWh per day in 21 months?).

I hope that's enough information, as I had to move the vacuum cleaner to get it, and I prefer it if that just sits there gathering dust.

Would it possibly have tripped for a dip in supply voltage?

This is the first time I've had to reset that, or had an issue anything like this, in the 21 months the system has been up and running. As said, we weren't doing anything unusual at the time - dinner was late that day, so the fan oven was on, but not heating, as were the heaters for the two reptile cages (which are different from the kids bedrooms), and that's the same as some point in nearly every day since installation.

I know MCBs can go funny when they're very old - I've replaced two of the ones in the house box for being over sensitive in the 20 years we've been here. But they certainly weren't new when we moved in.

I guess I'll just have to watch this one, and see if it goes again soon. If it does turn out to be a frequent problem, I suppose I'll have to replace it. That may mean learning how to isolate it from both mains (easy) and the inverter (not so sure). But it's at least tomorrow's problem, I hope.

Graham

A 32A breaker should be more than sufficient for a 5kw inverter unless you wire the EPS to run in bypass, but as you say there was no particular load on the system at the time so unlikely to be over current. The 100mA RCD should also be more than enough to cope with the transients - it could as you say be a problem on the grid side that has caused the breaker to trip, but also worth double checking that all the terminal connections are tight (i've seen problems with OB112 terminations being loose and arcing).

I don't much fancy getting inside the box to check the terminations. I can see potentially terminal problem there, as I'm not sure how to isolate the inverter. Hopefully, then, it's a grid side issue and one with a low frequency. If it only happens once a year or so, I probably won't do anything other than reset the trip and mutter a bit for a couple of days.

Graham