Lightning Strike Damage (months ago) Fluros BIO-T5SP-28DL.

[carlyai]

Just a heads up on these fluros.

The last big, close lightning strike (months ago) took out the house MOV's. 

There is no protection on the garage and the strike took out 6 fluros and my SONOFF Smart WiFi switch power supply. 

The fluros are model: BIO-T5SP-28DL. I opened one up and from visual inspection it seems a resistor has blown up in the circuit wizardry. Losing 6 at one time is not very economical and maybe a unit to stay away from.

So I've put them away for Ron and sometime figure out the resistor value, replace them and see if they work. 

[Crossy]

39 minutes ago, carlyai said:

So I've put them away for Ron and sometime figure out the resistor value, replace them and see if they work. 

 

They won't ????

 

That resistor is effectively a fuse, the switching FET is certainly also toast (shorted) which is why the resistor opened (when you tested the lights). You may get away with replacing both, if you can find values.

 

For the cost of a new T5 electronic ballast I'd just ditch the electronics and replace with a new ballast.

[Led Lolly Yellow Lolly]

Just as a matter of curiosity, when you say 'house MOVs', what are (were?) you using and where?

About the light fittings, I get through tens, sometimes hundreds of thousands of Baht per year replacing light fittings due to lightning. None of the brands, even Philips (ordinarily the most reliable brand IME) can't withstand nearby strikes. I wish I'd taken pictures of the floodlighting that got hit in October last year, they literally exploded. Internally, some of the old CFL luminaires we still had came apart sending glass showering down into reception and the toilets. I've had some luck protecting the more expensive light fittings with 3 MOVs per fitting in a delta between L, N and E but some transients are so massive nothing can really help you. We are very exposed and cover a large area of land, so we have worse luck than most. Lightning protection is a pet topic for me.

 

 

 

 

[carlyai]

9 hours ago, NilSS said:

Just as a matter of curiosity, when you say 'house MOVs', what are (were?) you using and where?

About the light fittings, I get through tens, sometimes hundreds of thousands of Baht per year replacing light fittings due to lightning. None of the brands, even Philips (ordinarily the most reliable brand IME) can't withstand nearby strikes. I wish I'd taken pictures of the floodlighting that got hit in October last year, they literally exploded. Internally, some of the old CFL luminaires we still had came apart sending glass showering down into reception and the toilets. I've had some luck protecting the more expensive light fittings with 3 MOVs per fitting in a delta between L, N and E but some transients are so massive nothing can really help you. We are very exposed and cover a large area of land, so we have worse luck than most. Lightning protection is a pet topic for me.

 

 

 

 

Hi NiSS, I use the MOV's  in the picture. Last lightning close strike took out the 3 of them at once. First time lost 3 together.

Power comes into the outside consumer unit and 3 phases go to the house consumer unit via 3 stabilizers to a SafteyCut brand RCBO and one phase goes to the garage from the outside consumer unit thru a RCBO.

The Safety Cut (set to 30mA) trips  if a lightning strike is close. I think it helps to protect the house electrics as I've never lost anything in the house due to incoming power or lightning. Most people on this forum are unsure of that claim.

So I have the MOV's  the stabilizers and the SafetyCut and a good earth system.

The garage has 3 rooms, fed from a Consumer Unit and normal circuit breakers. I have 10 of those fluros in the garage and only 6 and a power supply in the car part of the garage blew up (plus the RCBO tripped).

So it could be that the stabilizers or/and the SafteyCut tripping and the MOV' are helping protect the house.

Really you need to look at the pinned thread on MOV' in the Electrical Forum  as Crossy (moderator) has done a fair bit of work on lightning strikes and protection.

You could install a stabilised as it's like a big inductor, where the current build up lags the voltage and this could be helping. (I think that's right but the effects of LEO now occupy the area where my electrical theory used to reside. ???? )

Sorry can't upload my mov pics. Schneider brand movs.

 

[Led Lolly Yellow Lolly]

On 11/27/2020 at 10:49 PM, NilSS said:

I've had some luck protecting the more expensive light fittings with 3 MOVs per fitting in a delta between L, N and E

 

 

 

 

 

Further to my above comment, coincidentally I threw up some street lights last night, this is what I am doing with the MOVs. The model is S20K275 and I buy them in bags of 100 from https://www.es.co.th . . . This has massively reduced failures. . .

 

 

[johng]

3 minutes ago, NilSS said:

I threw up some street lights last night

Crikey what had you been drinking ????

[Crossy]

A word of warning about those little MOVs (I use loads of them too).

 

MOVs do wear out. Each time they stop a surge the threshold voltage decreases slightly, eventually the threshold gets below the actual supply voltage and the beast stays triggered. Of course this is not a good situation and the device gets very hot very quickly potentially leading to conflagration.

 

I've been using them for many years and have never had one actually fail in this manner, but it would be remiss not to mention it.

 

So if they're in an area with flammable building materials put them in a metal box.

 

The big whole-house units have a trip mechanism built in to prevent issues (it also operates the "expired" flag in the window).

 

This is what can happen, obviously a deliberate over-voltage but ...

 

[Led Lolly Yellow Lolly]

A quick blow inline fuse should take care of that.

[carlyai]

16 hours ago, NilSS said:

A quick blow inline fuse should take care of that.

Won't that defeat the MOV box setup? Soon as you get an energy spike the fuse is going to blow. Don't you just want to shunt the excess energy to ground and away from your connected equipment without having to replace components all the time?

 

[Crossy]

27 minutes ago, carlyai said:

Won't that defeat the MOV box setup? Soon as you get an energy spike the fuse is going to blow. Don't you just want to shunt the excess energy to ground and away from your connected equipment without having to replace components all the time?

 

Even a "quick blow" fuse is an order of magnitude slower than any lightning surge. But like I said, unless you have things around to catch fire I wouldn't bother, or put it in a metal box if worried.

 

You could put a 1A anti-surge fuse in the feed to the light and MOV, then if things do go awry you can see that the fuse is popped because the light won't work.

[carlyai]

14 minutes ago, Crossy said:

 

Even a "quick blow" fuse is an order of magnitude slower than any lightning surge. But like I said, unless you have things around to catch fire I wouldn't bother, or put it in a metal box if worried.

 

You could put a 1A anti-surge fuse in the feed to the light and MOV, then if things do go awry you can see that the fuse is popped because the light won't work.

I once saw all these boffins design boxes to count lightning strikes. Great, the boxes got to 1. You could tell because the box was blown to bits.

I don't think any fuses and lightning make sense.

[Crossy]

6 minutes ago, carlyai said:

I don't think any fuses and lightning make sense.

 

Don't install them then, I haven't.

 

My MOVs are either in an area where they won't set fire to anything or are in a metal enclosure.

[maxpower]

It should be noted that failing MOV's can start fires with only a small mains current flow often well below any overcurrent protection. The preferred method is to employ a thermal fuse in series with the MOV. Some circuits provide visual indication when a thermal fuse fails.

 

MOV's do not always fail in flames and often split open completely breaking the circuit. Its good practice  to occasionally inspect devices placed on supplies to expensive electronics.

 

[Led Lolly Yellow Lolly]

3 hours ago, carlyai said:

Won't that defeat the MOV box setup? Soon as you get an energy spike the fuse is going to blow. Don't you just want to shunt the excess energy to ground and away from your connected equipment without having to replace components all the time?

 

 

Ideally yes, all you want to do is shunt away the transients and everything keeps working thereafter. However, the handful of circumstances where I use a fuse would be on an equipment rack with expensive IT, Cisco switches etc etc, I'd rather have the fuse blow out of the circuit, providing further mitigation (both the L and N side are fused), and have the relatively minor inconvenience of replacing a fuse than several 30,000 Baht rackmount switches. If the fuse blows, the rack will keep running on batteries for 4 hours, plenty of time for someone to replace the fuse. I'll take a picture of my setup later. . .