Solar panel fire

gctest50

http://twitter.com/andrewbannister/status/881458888587051009


No one moved to there yet

quentingargan

I wouldn't rush to judgement here. There isn't anything particularly combustible in a solar PV panel and if panels did catch fire, the fire would spread up, not down, whereas the third floor was on fire in this case.

It is likely that the flames were appearing around the panels because there are gaps in the tiles for the mountings etc., but it is highly unlikely that the panels caused any fire.

Ubbquittious

quentingargan wrote: »

I wouldn't rush to judgement here. There isn't anything particularly combustible in a solar PV panel and if panels did catch fire, the fire would spread up, not down, whereas the third floor was on fire in this case.

It is likely that the flames were appearing around the panels because there are gaps in the tiles for the mountings etc., but it is highly unlikely that the panels caused any fire.

Not even the sheet of white plastic at the back of it? Though I must admit I have never tried burning one. Too costly

gctest50

An inverter connected to them would start a fire handy enough too

Anthony and Angela McIntyre spent £8,400 having the 20 panels installed on their roof three years ago.

But a faulty inverter in the loft triggered a fire which gutted most of the four-bedroom detached house.

The blaze started as the couple's younger daughter Chloe, 15, was lying in bed asleep and Mr McIntyre dashed inside the house to wake her and get her out.


http://www.telegraph.co.uk/news/earth/energy/solarpower/12092562/Solar-panel-malfunction-sparks-blaze-in-family-home.html

Phonicks

Thats terribal that he had to go into the burning house


It should be a law that you must have a smoke alarm in the center of every room that has a bed, chair or counch

Calahonda52

one should never ever let the facts get in the way of a good social media OMG/WTF/HANDA

It was not clear whether it was a faulty unit or faulty connection.
An inverter switches electrical current from AC to DC so it can be used in a stand-alone power system.

Avon and Fire Rescue Service said fires involving solar panels are rare


As for the bar chart: plants, not panels, but again one should never ever.....

Effects

Phonicks wrote: »

Thats terribal that he had to go into the burning house


It should be a law that you must have a smoke alarm in the center of every room that has a bed, chair or counch

I thought we did these days.

murphaph

If PV fires were any way common you'd never get insurance for a property with them fitted. insurance companies know exactly how risky they are.

deandean

I wouldn't put the inverter in the attic!

Gumbo

deandean wrote: »

I wouldn't put the inverter in the attic!

Where would you put it?
I was planning to put mine in the eaves space of the converted attic. Also planned on putting a smoke detector in the space also.

murphaph

They are going to be less efficient in a hot attic and you might also want to read something from the display (especially if the model has no data logger).

A utility room on the ground floor would be a better location.

quentingargan

Yes. The unit will start to derate when its internals get to a specific temperature, usually about 50 degrees centigrade. But if you are putting the inverter downstairs, you need to change the cable within the house to SWA or use steel conduit. It isn't good practice to run flexible solar cables buried in the wall. For that reason, most budget Part L installations have the inverter in the loft which is safe enough provided the inverter is mounted on a block wall and vented, and providing it is a modern sealed unit (most are usually IP rated for outdoor use)

deandean

An attic has no fire rating at all. There are lots of exposed timbers and membranes. I would not put an inverter, or a DVR, or anything else into the attic for this reason.
With your solar panels KC, possibly you could increase the cable 1 size, run it externally down the end wall and mount the inverter externally on the wall at ground level in a weatherproof enclosure?

gctest50

Calahonda52 wrote: »

one should never ever let the facts get in the way of a good social media OMG/WTF/HANDA

It was not clear whether it was a faulty unit or faulty connection.
An inverter switches electrical current from AC to DC so it can be used in a stand-alone power system.

Avon and Fire Rescue Service said fires involving solar panels are rare


As for the bar chart: plants, not panels, but again one should never ever.....

Calahonda52 wrote: »

...........

An inverter switches electrical current from AC to DC ..

Does it now ? must tell my one it'll be upset


Anyway a fire per week :

http://www.brisbanetimes.com.au/queensland/madonna-king-solar-panels-installations--in-queensland-spark-a-fire-every-week-20150617-ghqt0t.html



Madonna King: solar panels installations in Queensland spark a fire every week

Calahonda52

Calahonda52 wrote: »

one should never ever let the facts get in the way of a good social media

An inverter switches electrical current from AC to DC

Indeed such an appliance is a rectifier.

An inverter switches DC to AC by inverting the waveform. :rolleyes:

quentingargan wrote: »

But if you are putting the inverter downstairs, you need to change the cable within the house to SWA or use steel conduit. It isn't good practice to run flexible solar cables buried in the wall.

Why's that? If I had my way I wouldn't have any solid core.

sydthebeat

Phonicks wrote: »

Thats terribal that he had to go into the burning house


It should be a law that you must have a smoke alarm in the center of every room that has a bed, chair or counch

We do now

quentingargan

Sir Liamalot wrote: »

Why's that? If I had my way I wouldn't have any solid core.

MCS standard in UK considers DC cables from panels in the house to be a hazard because there is no fuse on the circuit normally that can protect it. Short circuit current is too close to working currents for a fuse to be effective.

Because PV array cables almost exclusively rely on double or reinforced insulation as their means of shock protection they should not be buried in walls or otherwise hidden in the building structure as mechanical damage would be very difficult to detect and may lead to increase instances of shock
and fire risk.

Where this cannot be avoided conductors should be suitably protected from mechanical damage, suitable methods may include the use of metallic trunking or conduit or the use of steel wire armoured cable in accordance with BS 7671.

Is there any merit to earth leakage protection and an earth referenced array?

Gumbo

murphaph wrote: »

They are going to be less efficient in a hot attic and you might also want to read something from the display (especially if the model has no data logger).

A utility room on the ground floor would be a better location.

quentingargan wrote: »

Yes. The unit will start to derate when its internals get to a specific temperature, usually about 50 degrees centigrade. But if you are putting the inverter downstairs, you need to change the cable within the house to SWA or use steel conduit. It isn't good practice to run flexible solar cables buried in the wall. For that reason, most budget Part L installations have the inverter in the loft which is safe enough provided the inverter is mounted on a block wall and vented, and providing it is a modern sealed unit (most are usually IP rated for outdoor use)

deandean wrote: »

An attic has no fire rating at all. There are lots of exposed timbers and membranes. I would not put an inverter, or a DVR, or anything else into the attic for this reason.
With your solar panels KC, possibly you could increase the cable 1 size, run it externally down the end wall and mount the inverter externally on the wall at ground level in a weatherproof enclosure?

My whole house is exposed currently so I have the chance to run the required cable to where I need it, but that chance will soon disappear as the house starts to get slabbed etc.

I have a small utility at ground floor that I could place the invertor in, would this mean I run a cable from the roof to this location?

gctest50

Sir Liamalot wrote: »

Is there any merit to earth leakage protection and an earth referenced array?

You can get arc-fault-interupters ( be like an ELCB except they look for the high frequenciesu developed by an arc )

quentingargan

kceire wrote: »

My whole house is exposed currently so I have the chance to run the required cable to where I need it, but that chance will soon disappear as the house starts to get slabbed etc.

I have a small utility at ground floor that I could place the invertor in, would this mean I run a cable from the roof to this location?

It would be good to run either SWA from the inverter location to the loft, or run steel conduit with two or four cores of solar cable, depending on whether you want to have one or two strings of solar panels.

In relation to earth referencing, most inverters don't have galvanic isolation and have earth leakage detection (because there is a small amount of leakage to ground from the grid caused by the injection process), so if there is any leg of the array earthed, the inverter will detect earth leakage and won't start.

quentingargan

quentingargan wrote: »

In relation to earth referencing, most inverters don't have galvanic isolation and have earth leakage detection (because there is a small amount of leakage to ground from the grid caused by the injection process), so if there is any leg of the array earthed, the inverter will detect earth leakage and won't start.

You're not selling me on this alternating current bandwagon Q. :P

Do they need galvanic isolators? It's only 2 diode pair so simple external mod.


I earth charge controllers; stops them being feathery (as well as mains fault protection on the ELV side) I don't generally exceed 120VDC though.





(excuse the mess. That's my man cave work in progress, I've tidied it since.)

quentingargan

Sir Liamalot wrote: »

Do they need galvanic isolators? It's only 2 diode pair so simple external mod.


I earth charge controllers stops them being feathery I don't generally exceed 120VDC though.

The grid tie inverter used for PV installations takes the DC from the panels, boosts it internally and then injects is directly into the grid. Older Sunny Boy inverters had a transformer on the grid side and some now have a high frequency transformer to isolate the grid from the DC.

If you don't have such a transformer, the inverter has RISO (resistance of isolation) and Ileak (current leakage) tests. If the resistance between the DC and ground isn't above 20Mohm, the system won't fire up. Likewise, if the Ileak exceeeds about 20mA, the system shuts down.

Either way, without a transformer, you can't ground the DC side of the PV array. (you can ground the frames of course for lightning protection if you wish)

High frequency is usually more hassle than it's worth imho. I don't think the frames are as important as the conductors.

Some advocate separate conduits for maximum mechanical resilience.
Suppose you could always use LED indicators or isolating contactors all a bit ho-hum though.