Solar system with Safe T Cut keeps tripping

[pedritosan]

I know very little about electrical systems. I hired a man who claimed to be a licensed electrician to wire the house. Many plugs were wired incorrectly and many of the wires were too small in gauge. The Safe T Cut ticked frequently. 
 

I had another electrician come and clean up the mess. But even he failed to insert proper ground wires. It’s not clear what he did but the Safe T Cut still cut the power. 
 

both electricians said it was “too sensitive”
 

The house has a Scnieder box and another electrician replaced the old Safe T Cut with a new one without a test button. The new one still cuts. 
 

I figured if I invested in an expensive solar system that they would come in and make it all right. But the solar guy did not ground the box. They also installed some ungrounded plugs. I hired yet another electrician, grounded everything and required everything that was improperly wired. 
 

the Safe T Cut now only clicks when it rains. I have no idea how to check the integrity of the solar system but when the Safe T Cut goes, the power stays on to some appliances. This was by design so the things would keep running when the grid goes out. 
 

then the solar system cut down and they told me to shut the solar breaker. Guess what? The power is still on for those appliances! 
 

any thought on how to fix this mess. 7th electrician?
 

 

[Dan O]

Check and make sure they didn't leave an old neutral to ground anywhere on any circuits. Since you don't have proper ground wires in the way they wired in older systems that was a common connection. With the safe t cut gfci you will fault out and trip.  I had that problem in our house when I upgraded and had to search around and finally found it and removed it.

[Crossy]

1 hour ago, pedritosan said:

The house has a Scnieder box and another electrician replaced the old Safe T Cut with a new one without a test button. The new one still cuts. 

 

This worries me somewhat.

 

Please can you post a photo of the new device? With no test button it likely doesn't have earth-leakage protection and if that's the case and it is still tripping well - Houston, we have a problem.

 

From your description it's very difficult to tell what's really going on but it sounds like a proper electrical survey is in order to find out where we are starting from.

 

Can you post a few photos of the kit, including your solar please?

 

[carlyai]

@pedritosanwhat physical location is your house?

If Crossy/you need another person to have a look, I know someone who may be able to help. 

[pedritosan]

Thank you so much for your help!

 

@Dan There are no old ground wires as the electrical system is new. I had to ask for each and every ground to be installed by an electrician that I hired.

 

@Crossy. Yes I'm worried, too. Here are some pictures...

 

@CarlYai...it would be much appreciated!

 

 

[pedritosan]

[pedritosan]

3 hours ago, carlyai said:

@pedritosanwhat physical location is your house?

If Crossy/you need another person to have a look, I know someone who may be able to help. 

@CarlYai I'm near Wat Umong where the kids live. I would love to have a referral. It would be very much appreciated! As you can see, the equipment is top notch and the installation doesn't look bad until one looks closely and sees drywall screws with no anchors, no ground line, etc, etc.

[pedritosan]

Also, is there a model of the Safe T Cut that I should upgrade to? Every electrician has told me "it is too sensitive," and recommended that I remove it. 

 

I honestly don't know if the Huawei inverter is providing adequate surge protection or if there should be another unit ahead of it. I'm not sure how the wiring between the different breakers works, either. I can turn off the input from the grid and run off of the battery, but only to the kitchen to keep the refrigerator running. If that is getting clean power from the battery, maybe it isn't a problem? I really have no idea.

[BritManToo]

31 minutes ago, pedritosan said:

Also, is there a model of the Safe T Cut that I should upgrade to? Every electrician has told me "it is too sensitive," and recommended that I remove it. 

 

I honestly don't know if the Huawei inverter is providing adequate surge protection or if there should be another unit ahead of it. I'm not sure how the wiring between the different breakers works, either. I can turn off the input from the grid and run off of the battery, but only to the kitchen to keep the refrigerator running. If that is getting clean power from the battery, maybe it isn't a problem? I really have no idea.

Most inverters are very sensitive to leaks, and will shut themselves off if what goes out the live doesn't return to the neutral, so no need to have anything (apart from simple fuses) after the inverter. I don't have the o/p of mine earthed either, it's supposed to sort itself out.

 

I know as my daughter managed to short it out through her hand. It had turned itself off before she even felt it.

[Crossy]

OK firstly, your new Safe-T-Cut DOES have a Test button ???? The big yellow thing with a T on it ???? 

 

My worry was that Safe-T-Cut do make units with no RCBO functionality, but you're good to go.

 

Did your solar installer leave you with any form of diagram? I'm assuming your Huawei is running grid-tie with the EPS output running the kitchen to keep the juice on when the grid is down.

 

When does the Safe-T-cut trip, any specific times (rain?), do you have outside lighting or outlets that may have let the damp in?

 

Any upgrade would be to individual Schneider RCBOs for the "risky" circuits (water heaters, outdoor lighting and outlets etc.) possibly leaving less risky circuits (indoor lighting) unprotected. If something untoward happened only that circuit would go off.

 

[carlyai]

2 hours ago, pedritosan said:

Thank you so much for your help!

 

@Dan There are no old ground wires as the electrical system is new. I had to ask for each and every ground to be installed by an electrician that I hired.

 

@Crossy. Yes I'm worried, too. Here are some pictures...

 

@CarlYai...it would be much appreciated!

 

 

Hi, I'll let Crossy work his magic.

If at the end you still need someone to take a look, I'll see where my friend is. :)

 

[pedritosan]

@Crossy. 555 well now you know my level of sophistication here. When I press that button, the system turns off. Is that normal?

 

Yes, the system is AC-coupled. To run it off-grid, I simply cut the power on the Safe T Cut. But he did not leave me with a diagram. I asked him whether he has ever installed a Huawei battery before and he was a bit evasive, but it was through a translator. I only need one more battery to go off-grid anyway.

 

The Safe T Cut trips every time it rains. Nearly immediately after it starts raining. So, I assume water is getting in somewhere. There are 2 outdoor outlets I could probably change to Schneider RCBOs and see if that helps. Thanks for your advice!!

[Crossy]

Yes, pressing Test should turn everything off ???? 

 

You could try turning off the breakers for the outside kit and see if that makes any difference when it rains. Does the Safe-T-Cut trip out again if you reset it?

 

Did you get a price for the Huawei battery packs? A couple of other members are looking for them and the $$$ being asked is frightening. Sadly, being high-voltage battery packs 3rd party units are like rocking-horse droppings ???? 

[lopburi3]

The key to finding issue is to turn all breakers off when you lose Safe-t-cut power and reset Safe-t-cut - then turn on one breaker at a time until it trips again.  Reset and turn on all other breakers except the one that tripped.  Then look at what does not have power - something on that breaker is causing cut off - likely outside outlet if immediate at start of rain - or something else getting wet fast.  As for some items staying on they often do not put everything on Safe-t-cut.

[pedritosan]

26 minutes ago, Crossy said:

I'm assuming your Huawei is running grid-tie with the EPS output running the kitchen to keep the juice on when the grid is down.

 

I think that is what he did. So, if he does that for the whole house, I'm guessing we don't need any surge protection, voltage regulation, etc., since we will not be connected to the grid. But then the Safe T Cut will no longer be on the circuit at all. Also, if there is a ground fault in the kitchen, I'm guessing we are out of luck.

[pedritosan]

7 minutes ago, lopburi3 said:

The key to finding issue is to turn all breakers off when you lose Safe-t-cut power and reset Safe-t-cut - then turn on one breaker at a time until it trips again.  Reset and turn on all other breakers except the one that tripped.  Then look at what does not have power - something on that breaker is causing cut off - likely outside outlet if immediate at start of rain - or something else getting wet fast.  As for some items staying on they often do not put everything on Safe-t-cut.

Amazing. That is super helpful! This forum is great and you all are life savers! Now I feel like I can handle this situation.

[Crossy]

18 minutes ago, pedritosan said:

I think that is what he did. So, if he does that for the whole house, I'm guessing we don't need any surge protection, voltage regulation, etc., since we will not be connected to the grid. But then the Safe T Cut will no longer be on the circuit at all. Also, if there is a ground fault in the kitchen, I'm guessing we are out of luck.

 

The inverter itself should provide ground fault protection on its output side, if anything ourSofar is a little too enthusiastic.

 

You would normally run in "grid-assist" mode rather than fully off grid, so if there's no sunshine and your batteries are dead the inverter will feed through from the grid to your loads. All things being equal you may never notice which supply you're on.

 

[McTavish]

As an aside, did you deal with Lanna Solar owner, the guy I refer to as the 'mad professor'.  I forget his name, Uwe __ IIRC.  Are your PVCells fully imported or ones he makes locally, and are they Earthed independently of your house circuits?  Dampness entering the PV to Inverter circuit may be enough to trip the breaker.

 

Crossy is the expert and may elaborate or correct my 2 satangs worth.

[bluejets]

On 8/6/2023 at 7:31 AM, pedritosan said:

The Safe T Cut ticked frequently. 

Most of these nuisance trips can be eliminated by getting away from this long haul install of one only safety-cut device(usually as a main switch)

Far better to use a 60A breaker for the main switch ( actually cheaper than an isolator in some instances and a requirement in some countries) and then install separate circuit combos ( circuit breaker/safety switch) on each circuit.

Apart from that, the "trips when it rains" suggests some exterior fault.

Not all that difficult to find if you have a megger and the right man for the job. Entails isolating all circuits and testing independently.

[pedritosan]

On 8/6/2023 at 1:56 PM, Crossy said:

 

The inverter itself should provide ground fault protection on its output side, if anything ourSofar is a little too enthusiastic.

 

You would normally run in "grid-assist" mode rather than fully off grid, so if there's no sunshine and your batteries are dead the inverter will feed through from the grid to your loads. All things being equal you may never notice which supply you're on.

 

That is great. Sometimes, the system randomly powers down in off grid mode. I will ask the installer about grid assist.

[pedritosan]

On 8/6/2023 at 2:14 PM, McTavish said:

As an aside, did you deal with Lanna Solar owner, the guy I refer to as the 'mad professor'.  I forget his name, Uwe __ IIRC.  Are your PVCells fully imported or ones he makes locally, and are they Earthed independently of your house circuits?  Dampness entering the PV to Inverter circuit may be enough to trip the breaker.

 

Crossy is the expert and may elaborate or correct my 2 satangs worth.

Hi name is P Non. They are from China. A very good brand--545W Longi panels. They were not originally earthed independently, and a competitor pointed out that they had no pictures of battery installs on their website. It took them an extra day to figure out how to put the battery in. I wish there were a mad professor involved, as they did a *lot* of installs, but all very basic ones. I'm presently making my way through the circuits as Crossy suggested. I think I identified the bathroom as the problem. The bathroom had just been rewired to add grounds and check the polarity, etc. So, I will ask that guy to come back. 

 

The place is damp for sure!

[pedritosan]

On 8/7/2023 at 6:39 AM, bluejets said:

Most of these nuisance trips can be eliminated by getting away from this long haul install of one only safety-cut device(usually as a main switch)

Far better to use a 60A breaker for the main switch ( actually cheaper than an isolator in some instances and a requirement in some countries) and then install separate circuit combos ( circuit breaker/safety switch) on each circuit.

Apart from that, the "trips when it rains" suggests some exterior fault.

Not all that difficult to find if you have a megger and the right man for the job. Entails isolating all circuits and testing independently.

555 That is a pretty big "if." I've been through quite a few electricians, and so for Crossy is the only one who advised to try one breaker at a time to isolate the circuit--something that should have been obvious to me. I will look into putting a separate safety switch on each circuit and then running the entire solar system through the safe-t-cut.

 

Now, I have to see if I can afford another battery and go completely off grid.

[McTavish]

1 hour ago, pedritosan said:

Hi name is P Non. They are from China. A very good brand--545W Longi panels. They were not originally earthed independently, and a competitor pointed out that they had no pictures of battery installs on their website. It took them an extra day to figure out how to put the battery in. I wish there were a mad professor involved, as they did a *lot* of installs, but all very basic ones. I'm presently making my way through the circuits as Crossy suggested. I think I identified the bathroom as the problem. The bathroom had just been rewired to add grounds and check the polarity, etc. So, I will ask that guy to come back. 

 

The place is damp for sure!

Ok, a different company then. 

 

I also have the 550w Longi panels but Earthed independently of both house and Inverter AC side to avoid tripping by small appliances: HW heater, iron, kettle etc.  2 x Earthing rods were driven into the ground specifically.

[sometimewoodworker]

6 hours ago, pedritosan said:

555 That is a pretty big "if." I've been through quite a few electricians, and so for Crossy is the only one who advised to try one breaker at a time to isolate the circuit--something that should have been obvious to me. I will look into putting a separate safety switch on each circuit and then running the entire solar system through the safe-t-cut.

 

Now, I have to see if I can afford another battery and go completely off grid.

FWIW Though you can have multiple RCCBs on a single feed you really really need to know what you are doing and why you are stacking them and that they are correctly (differently) configured.

 

So in short only 1 RCCB on 1 circuit.

 

[lopburi3]

10 minutes ago, sometimewoodworker said:

So in short only 1 RCCB on 1 circuit.

I would always protect point of use water heater run with RCCB as well as having on unit itself - often that wire is exposed at some points.

[sometimewoodworker]

4 minutes ago, lopburi3 said:

I would always protect point of use water heater run with RCCB as well as having on unit itself - often that wire is exposed at some points.

I agree that shower water heater mostly have a built in RCCB and they are exempted from the only 1 RCCB rule

 

[sometimewoodworker]

On 8/6/2023 at 1:24 PM, Crossy said:

Did you get a price for the Huawei battery packs? A couple of other members are looking for them and the $$$ being asked is frightening. Sadly, being high-voltage battery packs 3rd party units are like rocking-horse droppings ???? 

What is the voltage? As LiFePO4 batteries are like rabbits on AliExpress, though the prices are not cheap and I have no idea of the availability to Thailand, they are all offering “free shipping” so the prices include that cost.

[Crossy]

10 hours ago, sometimewoodworker said:

What is the voltage? As LiFePO4 batteries are like rabbits on AliExpress, though the prices are not cheap and I have no idea of the availability to Thailand, they are all offering “free shipping” so the prices include that cost.

 

Nominally 450V DC which places them firmly in the "not really DIY" area.

 

Huawei 5kWh unit 162,000 Baht!

 

https://www.solartech-center.com/product/1006/huawei-battery-powermodule-luna2000-5k

 

By contrast an off-brand 48V, 5kWh pack is around 60,000 Baht and if you DIY around half that.

 

 

 

[sometimewoodworker]

22 minutes ago, Crossy said:

Nominally 450V DC which places them firmly in the "not really DIY" area.

The master of understatement!!!

 

At that kind of voltage and power DIY has a reasonable chance of producing a crispy critter I would imagine 

[TwentyBaht]

Would just like to mention, ants nesting in electrical components and devouring the plastic a common problem in Thailand.  I've experienced this with a computer component, a router circuit board, a television, and a hot shower unit.  And recently in my new house after an all day rain the RCBO tripped twice within about 30 minutes and then wouldn't stay in.  Caused by an outside plug receptacle which was under roof but enough dead ants had collected inside the receptacle and a few hours of near 100% humidity provided enough sensitivity to trip the RCBO.

 

Will add, it was the next day before I could start looking for the problem and the RCBO was still tripping on this circuit, so it would appear dead ants hold their moisture well.