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Discussion Starter · #1 ·
I have an Indra Smart+ charger installed by ChargedEV with a matt e box rather than an earth rod. I also have solar panels.

This Summer the charger has been tripping out regularly, probably once a day more. The problem is due to high voltage - more than 253V - which trips the Matt e box. The voltage is shown on the solar inverter and the maximum daily voltage is often above 256V.

There have been times when I haven't been able to use the charger because of this. Sometimes turning on the oven has allowed it to restart.

I think the problem is made worse by the solar panels as it seems more of a problem on sunny days, but it has happened on cloudy days. It usually isn't a problem at night, but I have had 3 charges fail at night.

ChargedEV tried to fit an earth rod but couldn't get a good enough earth and said I should contact my DNO. The DNO fitted a voltage monitor in the fuse box for a couple of weeks and have just informed me that the voltage is within allowed limits.

I'm not sure where to go next as ChargedEV have said the equipment is OK and Northern Powergrid say the voltage is OK. Any suggestions?
 

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The DNO voltage monitor will be calibrated so is correct, the maximum allowed voltage is 253V, this suggests the matt-e box is the problem, its set wrong. I thought the indra smart box did its own PEN testing and did not need a matt-e?

Edit : having seen @Mike Schooling 's comments I hope the DNO calibrate their instruments, I'd be troubled if they did not.
 

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Not the first time this has happened. The matt-e does this because it uses a crap way of trying to guess if there may be a PEN fault, an inherently non-specific voltage sensing technique that will false trip when there isn't actually a PEN fault at all, as you've found. There are very much better open PEN fault protection devices around, that do not use this daft voltage sensing method, and so are not sensitive to false alarms like this. You're not the first to have this problem, someone else, either on here or on the Tesla forum had exactly the same problem, and ended up ripping the matt-e out and replacing it with a proper open PEN fault device, like the Viridian unit.

FWIW, the newer Indra charge point has a very good built-in open PEN fault protection system built in, so doesn't need a separate device to do this. Perhaps @Mike Schooling might like to comment?
 

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This will be a V3 unit designed for 17th edition wiring regs (Smart+) hence the Matt:e box being used. We stopped making them in March 2020.

If the DNO is correct and the voltage is truly within the limits then the Matt:e box is the problem.

If you can share the MAC ID from the side of the unit I can have a quick look at logs. issue is we have power to us cut so I'll only see voltage before it trips. Will give a good idea if it is tripping early though.

Sent from my SM-N976B using Tapatalk
 

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Discussion Starter · #5 ·
This will be a V3 unit designed for 17th edition wiring regs (Smart+) hence the Matt:e box being used. We stopped making them in March 2020.

If the DNO is correct and the voltage is truly within the limits then the Matt:e box is the problem.

If you can share the MAC ID from the side of the unit I can have a quick look at logs. issue is we have power to us cut so I'll only see voltage before it trips. Will give a good idea if it is tripping early though.

Sent from my SM-N976B using Tapatalk
Thanks for the reply.

I can see the mains voltage on my solar inverter which is next to the matt:e. When I've been there at the time it's tripped the voltage has always been high (253V or more). This has been on 2 or 3 occasions, including when the chargedEV engineer was here to fit the earth rod. Also I checked the maximum voltage most days whilst the DNO equipment was here and this was always above 253V.

The last time I know it tripped was early afternoon on Friday (13 August). I had to use the Granny charger in the end as the charger wouldn't reset for long enough to start a charge.

I've attached a picture of the label showing the MAC address.
Font Signage Number Rectangle Parallel
 

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There can be an issue with voltage drop, causing the supply closer to the PV inverter to exceed the 253 VAC upper limit, but not cause the supply at the incoming fuse to get that high. As the DNO responsibility is to comply with the ESQCR limits at the incoming supply only, they will measure it there, and will not take responsibility for something on the consumer side that's increasing the voltage away from the incomer.

This happens because the current flowing from the inverter out to the incoming supply creates a voltage drop along the cable, perhaps only a few volts, but if the incoming supply is already close to the upper limit then that can easily push the consumer side up above it. Because the matt-e is a very dumb voltage sensing system, it will erroneously trip when this happens, because it's too dumb to detect that this sort of modest over-voltage is not really caused by a PEN fault.

The modest over-voltage probably isn't an issue, as most appliances are fine up to around 260 VAC to 265 VAC, so the issue is just really the nuisance trips from the matt-e. There's no fix for this, it's just the way the thing is designed. It is designed to trip out if the supply voltage dips below 207 VAC or peaks above 253 VAC, and it cannot be adjusted.
 

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Had a super quick look at logs.

We can see the unit regularly getting to ~253v and then losing power (because the Matt:e box cuts it).

This is definitely a DNO issue to resolve - if your PV inverter and EV charger are both tripping then as Jeremy says it'll be that voltage at the service head (where DNO responsibility ends).

If DNO can/will not do anything then your workaround options are an Earth Rod or maybe ask ChargedEV if they'll move you onto a Smart PRO - warranty for that is owned by OVO so you never know.

Sent from my SM-N976B using Tapatalk
 

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Discussion Starter · #8 ·
Had a super quick look at logs.

We can see the unit regularly getting to ~253v and then losing power (because the Matt:e box cuts it).

This is definitely a DNO issue to resolve - if your PV inverter and EV charger are both tripping then as Jeremy says it'll be that voltage at the service head (where DNO responsibility ends).

If DNO can/will not do anything then your workaround options are an Earth Rod or maybe ask ChargedEV if they'll move you onto a Smart PRO - warranty for that is owned by OVO so you never know.

Sent from my SM-N976B using Tapatalk
I've not tried going back to the DNO because their letter made it pretty clear that they have checked the supply and as far as they are concerned it's within limits, so I doubt this will get me anywhere.

I have had an overnight charge fail recently when the charger was plugged in after dark so the problem can't be just down to the solar panels, although it does seem to be more of a problem during daylight. I normally charge overnight using the boost option on the charger and the timers in the car. When the charge failed I suspect the charge point restarted without the boost option and didn't start the charge because I had no schedule set up in the app. I have now changed this and don't use boost and have set up 8am in the app for the car to be ready. I still use the car timers but think this should be more robust because it doesn't rely on boost being selected if the charger restarts.

I just have been offered a replacement version 4 charger at half price (which is more than I originally paid in January 2020 after the grant). This sounds like the best option to resolve the nuisance trips so I just need to decide whether to pay up or live with the trips.
 

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My matt:e box looks to have tripped a few days ago. I can't work out how to reset it though. The installer did show me but I've forgotten and when I try to push the breaker up it just falls down again.
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