Where is your PV inverter? Reluctant to put them in house...

[Carrerahill]

I am increasing my PV array next month and this will involve switching to a bigger inverter with dual MPPT, I need to tweak things and move things about a bit anyway so it's time to reconsider the location of the inverter. I really don't like the idea of them in my house.

 

The fairly common place is for them to go in the loft, in my case south facing eaves, not ideal. I design PV system into buildings all the time, commercial inverters go anywhere from the north side of a lift shaft overrun to the plant room, in flatted developments it's fed into the landlord supply so the inverter can go anywhere from a ventilated riser cupboard to a roof void. So it's common enough, but I am still not 100% sold on them going inside, it is possibly an irrational fear, perhaps as a building services consultant I understand all to well the weakness of these systems and the point(s) of failure which can lead to fire.

 

I have made an executive decision to, for example, remove all the MC4 connectors from within the house. I am going to replace the panel mount MC4 connectors on the inverter with a small cable gland and dress the DC cables directly into the inverter and terminate them directly into the screw terminals on the built-in DC isolator (I'll cross the bridge that is the warranty issue if it comes to it). That removes 12 points of failure (crimp on each side of the MC4 and the interface between the pins over 2 strings).

 

However, it got me thinking, the inverter is IP65, it could go outside, I get mixed information when you do a search on this, some articles say, yes great idea, outside in the shade, could not be better, others comment about the inverters being exposed to the elements etc. I get that, but there is no reason why I couldn't protect the inverter further. I had considered a feeder pillar (yes like you see on the street), but I think that would look too commercial, so I considered a wall mounted enclosure, something like a 800x800x250mm enclosure I could mount low down on the outside, side of the house, I can get one with fans which I could run via a temperature sensor, but a bit pricey for all this.

 

I also considered putting them in the garage, I could mount them low, so if a fire did occur the concrete floor and block walls are not going to combust, but I would then need to run the DC cables down the house, across the path somehow (no spare ducts) and into the garage, probably totalling about 30m runs, I considered making a double/triple fireboard lined plant area in the eaves and adding good insulation to stop solar gain via the roof and mechanically ventilate it on a temperature sensor. 

 

So, I think I am just looking for some collective input from the forum, some thoughts and ideas, some irrational fear counselling maybe...

 

 

[SteamyTea]

As they generate thermal energy as part of normal operations, use that energy.

So somewhere that can vent to the house when it is cold, or vent to cooler external air when hot.

Real shame they are not liquid cooled, that would make life a doddle.

[Carrerahill]

10 minutes ago, SteamyTea said:

As they generate thermal energy as part of normal operations, use that energy.

So somewhere that can vent to the house when it is cold, or vent to cooler external air when hot.

Real shame they are not liquid cooled, that would make life a doddle.

Agree 100% with all of that. It's just if there was ever far too much thermal energy I would worry a bit!

 

Maybe I line the area in fireboard and be done with it...

 

 

[SteamyTea]

Just now, Carrerahill said:

if there was ever far too much thermal energy I would worry a bit!

They start serious clipping of excess, then shut down. Why lofts where never a good place for them. Especially true if the inverter is undersized.

 

 

[Carrerahill]

4 minutes ago, SteamyTea said:

They start serious clipping of excess, then shut down. Why lofts where never a good place for them. Especially true if the inverter is undersized.

 

 

We are going to be oversized on the inverter but within efficient parameters as the start-up voltage is quite low, so it should never get too hard a workout. 

[S2D2]

Integrated garage for mine. As above I would expect them to manage excessive heat by reducing output rather than just catch fire. Either way unwanted behaviour so anywhere the air temp won't be too high for the passive heatsink. Follow manufacturer instructions for outside if needed, though any batteries would get too cold outside imo.

[ProDave]

So do you know of history of MC4 connectors catching fire?  What other reason do you have to eliminate them?

 

From a purely technical point of view I would always try and put the inverter close to the consumer unit in terms of cable length.  In some cases, particularly with high mains voltage, inverters tripping or limiting due to over voltage can be an issue.  On the other hand longer cables and hence volt drop on the DC side will not cause such errors.

 

Although they may be rated as IP65 I would not be happy with them completely outside, but under a canopy perhaps to keep the rain off them.

[TonyT]

My system has been in the loft for 10 years with no dramas.

 

rafters directly above the inverter had kingspan type insulation fitted between them.

 

if I was more worried I would connect to smoke detection and maybe fit something like this

https://www.fusebox.shop/products/consumer-unit-fire-protection-system?variant=39850464739411&currency=GBP&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&gclid=EAIaIQobChMI9eS0wf-w_gIVl7PtCh3tAwYwEAQYAyABEgJWmvD_BwE

 

[SteamyTea]

15 minutes ago, TonyT said:

My system has been in the loft for 10 years with no dramas.

Do you know the efficiency losses from working it in a higher ambient temperature?

[TonyT]

Nope

manufacturers instructions advise that temps should be below 40 Deg C to ensure optimal operation

 

the operating temperature range is -25Deg C to +60 Deg C

 

[jamieled]

We have panels mounted on a timber frame. Inverter mounted to the back of that. Crude wee wood canopy over the top so it's mostly open but protected from the prevailing weather. Has worked fine.

[LA3222]

Mine is outside, on the wall and exposed to the finest weather Lincolnshire can throw at it. 

 

What's the issue.

 

My house melts as it is, sod having that inside. 

[Radian]

At 95% efficiency A 3kW inverter is going to dissipate around 150W so it's not more than having an extra person in the house. The devices themselves are extremely unlikely to catch fire (unlike batteries). They just go pop and blow a fuse if things go South.

[Pocster]

29 minutes ago, LA3222 said:

Mine is outside, on the wall and exposed to the finest weather Lincolnshire can throw at it. 

 

What's the issue.

 

My house melts as it is, sod having that inside. 

+1 - outside on a wall - sorted 

[Ronski]

My 2015 installed 3.68kW SolarEdge inverter is in the loft, not ideal but it was the only place it could go, and it's only a short period of the year that it gets rather warm in the loft.

 

My 8kW Quattro and associated batteries are in the detached garage, new array on the double garage flat roof.

[Dillsue]

We've had a Solaredge SE4000 in the loft since 2015 and the heat sink gets luke warm in the middle of summer. Mount it on a sheet of Hardie backer if youre concerned about it setting fire to the loft. If you use an inverter with a plastic case then more chance of that melting and catching fire if the electronics go south. If youre using a cheap inverter thats not on the ENA database then I'd be more concerned about quality than something the manufacturer has invested more time and effort in testing.

 

I'm not sure a quality MC4 connector poses much risk if crimped with the correct tool. Ive seen a connector crimped with a pair of pliers that the cable pulled out of and thats likely where the risk with the connectors lies?.

Edited April 17, 2023 by Dillsue

[Ronski]

Both of mine are on Hardie backer board. As Dillsue says, the problem with MC4 connectors is only when they've been poorly installed, or poor quality tools / connector's are used. 

[Carrerahill]

Many replies and lots of info, forgive me if I do not respond to each directly but to respond to some comments, yes it seems many of you have got the typically combustible surroundings that so many PV inverters have, I think I have decided, well I have, because I only bought enough cable to do it this way, I will put the inverter into the eaves space, it will be mounted onto a Unistrut frame on a brick wall, I will line the roof above with 2 sheets of plasterboard to make myself a little happier. I am going to monitor the temps this summer and see how hot it gets out there, if the temps get too high I will add a duct to cover this area for ventilation. 

[Alan Ambrose]

Add a smoke detector maybe?