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« Solar heat illustrated - Josh 322 | Main | The Iris Hypothesis from the archives »
Tuesday
Apr212015

Solar heat

A fire at Hove Town Hall was caused by solar panels on its roof, it emerged today.

"The source of the fire is believed to be an electrical fault with a solar panel on the roof. An investigation is under way."

The council said all its solar panels were checked annually, with those at the town hall checked two weeks ago.

ESF&RS said solar panels were no more dangerous than any other electrical product.

Although according to this website, this is not actually true

Research commissioned by the DCLG and carried out by BRE on fire safety and solar electric/photovoltaic systems, identifies the major obstacle facing firefighters: “In contrast to the power used by conventional mains electrical equipment, the power that PV systems generate is DC (direct current) and parts of the system cannot be switched off. DC installations have a continuous current, making them more hazardous (volt for volt) than normal AC (alternating current) electrical installations.”  

The issue is that a household’s AC supply can easily be shut off by firefighters, however, the DC current supplied by the solar panels will also be generating as long as the sun is out.

The whole article is pretty interesting, pointing out for example that if a fire breaks out in your solar panels, it is not going to get picked up by your smoke detectors.

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Reader Comments (55)

Hyperthemania: the failure of your link could possibly be because you prepared the message off-site – on Word, say – then copied it over, on-site. When you do that, you have to replace the quotation marks before you “Create post”. To check, press “Preview post”, then test your link.

Apr 22, 2015 at 9:52 AM | Registered CommenterRadical Rodent

The concept of killing the output of your PV inverter is called 'anti-islanding'.

It is to prevent 'little islands' of mains voltage being present and killing or injuring electrical supply staff during blackout repairs.

All equipment designed for use in a grid connected situation has this facility 'hard wired' into the inverter.

Of course you can circumvent 'anti-islanding' but if anyone is killed or injured as a result then I suspect a long prison sentence would result.

Petrol filling stations have an external 'fire brigade cutoff switch' mounted on an outside wall about 12 feet high which kill the power to the petrol pumps.

I suspect houses with PV will eventually be forced to follow this rule.

I can envisage angry non-PV house owners in an adjacent semi or terraced house when they see the firefighters waiting till dark, to put their neighbours house fire out.

It is small satisfaction that all the firefighters could do is drench your house to stop it burning.

Is this one reason why global warming increases flood damage - adjacent houses being drenched due to PV fires?

Apr 22, 2015 at 12:47 PM | Unregistered CommenterSteve Richards

So - perhaps the adverts should now be modified a follows:

'Generate your own electricity..!

Generate your own unstoppable roof fire - stand and watch it with the firefighters..!

Pay extra insurance..!

Warn your (terraced; semi-detached) neighbours that their homes are at risk..!'

Haven't missed anything, have I..?

Apr 22, 2015 at 1:00 PM | Unregistered Commentersherlock1

"an AC installation arcing is mostly self-damping since voltage goes through zero 50 times per secod (60 in the US). In an DC installation arcing simply goes on until something melts."

posted Apr 22, 2015 at 9:51 AM by: tty

Um, zero crossings occur twice a "cycle" in a bipolar sinusoidal mains, for 100 times a sec UK (120 in the US and many others countries). Ask me how I know. As a sideline as an ARS operator I do mains RFI location by radio DF techniques; it helps to verify the arc characteristics as to once a cycle (the breakdown arc strikes once per pos or neg sinusoidal excursion) or strikes multiple times (as in arc extinguishment after strike followed by another strike.) Open-air breakdown is usually once per excursion whereas insulator breakdown can be multiple strike/extinguish per pos or neg excursion from zero volts.


Also not considered in any of this, is, lightning-caused damage due to a) direct strikes or b) induced damage caused by nearby strikes or 'hits' on the distribution circuits (including the neutral or 'ground') up or down the line a bit.

_Jim

Apr 27, 2015 at 3:41 PM | Unregistered Commenter_Jim

nice information

Dec 20, 2017 at 10:38 AM | Unregistered Commenterjim

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