Electrical surge protection.

[up2you2]

Last Friday night I huge clap of thunder, which shock my roof tiles and had them clattering all over the place.
Following morning still no power, and on examining my surge protection box, it had taken a direct hit, with the attached parts having to be replaced.
In the light of this, I am now being offered an additional Schneider Surg Protection Device.

I wonder who has gone down a similar route, and if so what kind of success they have had, in so much as never having to replace the said items.
In theory I thought one could set up some kind of trip switch, that would take the lightning power surge, then you can manually reset it?

[Crossy]

What's the spec. on that Schneider unit?

 

The problem with lightning surges is that they are far too fast for any electro-mechanical device to operate.

 

The MOVs in the SPD's are very fast, but have to have enough current capability to snub the likely surges. They reset by themselves but do wear out (hence the "replace" window).

 

We have a 100kA SPD on our incoming supply where it enters the house, then smaller 60kA units on the feeds to the solar on the car port. Delicate or expensive technology gets local good quality, plug-in protectors too.

 

I think you are going to need another box with a nice meaty SPD mounted right next to your incoming MCCB as a start.

[up2you2]

1 hour ago, Crossy said:

What's the spec. on that Schneider unit?

 

The problem with lightning surges is that they are far too fast for any electro-mechanical device to operate.

 

The MOVs in the SPD's are very fast, but have to have enough current capability to snub the likely surges. They reset by themselves but do wear out (hence the "replace" window).

 

We have a 100kA SPD on our incoming supply where it enters the house, then smaller 60kA units on the feeds to the solar on the car port. Delicate or expensive technology gets local good quality, plug-in protectors too.

 

I think you are going to need another box with a nice meaty SPD mounted right next to your incoming MCCB as a start.

I do not know the specs on this Schneider unit, but from what you are saying here, it sounds as if Keehin are on the right track.

15 years and this is the first major failure, so perhaps I've been lucky.

[Crossy]

I'd be looking at something like this right after your main incomer.

https://www.lazada.co.th/products/surge-ac-ly1-b80-80ka-3-l1-l2-l3-n-pe-ac-surge-3p-80ka-i2809012215-s10238081180.html?

 

[carlyai]

14 hours ago, up2you2 said:

I do not know the specs on this Schneider unit, but from what you are saying here, it sounds as if Keehin are on the right track.

15 years and this is the first major failure, so perhaps I've been lucky.

I broke open one of these Schneider units and for near B2000 each it had B200 of gear inside, so changed my setup to what Crossy recommended.

[Led Lolly Yellow Lolly]

I'm thinking about constructing my own SPD devices because we're losing loads of televisions and aircon boards. I have bags of MOVs I put in a delta on outdoor lighting, works a treat, but I want something that'll take a big hit that I can put on upstream 3-phase distribution panels. I'm still researching this but it seems to me these industrial strength surge arrestors are little more than banks of small MOVs in parallel. I could construct these myself with bus bars, some heavy cables and a case.

 

In any case it's not just lightning you need to worry about. I've been having problems with snakes bridging thousands of volts onto the LV side of transformers (why I'm losing TVs etc etc). This is what a Golden Tree Snake looks like after putting itself across 32,000 volts. This one blew itself off the circuit and fell to the ground (it basically just exploded from the inside out). Others are little more than charred bones when they're pulled down. . .

 

 

Edited November 25, 2021 by Led Lolly Yellow Lolly

[tjo o tjim]

No MOV is going to protect you against a snake bridging HV-LV.  At that point you want an air gap arrester and an over-voltage trip on your main— you want defense in depth.  The industrial SPDs typically have capacitors in parallel to the MOVs to absorb the instantaneous peak of the transient; it will both extend the life of the MOV and significantly reduce the let-through energy.  You can chain MOVs in series for higher clamping voltage or parallel for increased energy, or a series-parallel arrangement as you need… but you get all kinds of opportunities for problems.  It’s something I would want a UL or TUV label on and from a legitimate source.

[Led Lolly Yellow Lolly]

I'm not sure how high the transients are but I doubt more than a couple of thousand volts are making it into the panels (I'm making really wild guesses here). The problem is sometimes the snake doesn't get blown off, and there is sufficient resistance for it not to burn up in seconds. There are phase to phase/neutral arresters of some kind all over the place that the PEA deployed when they built this system for us, but I guess they have a 'life' too. I've never pulled one down to dismantle it so I don't know what they are specifically but they look like gapless Type 2 MOVs, like this I posted in another topic ages ago. . .

 

In any case, I agree with you, anything I can do with my soldering and my boxes of stuff won't stand up to something built for the job, and in layers.

 

Edited November 28, 2021 by Led Lolly Yellow Lolly

[Boyn]

On 11/3/2021 at 3:31 AM, Crossy said:

What's the spec. on that Schneider unit?

 

The problem with lightning surges is that they are far too fast for any electro-mechanical device to operate.

 

The MOVs in the SPD's are very fast, but have to have enough current capability to snub the likely surges. They reset by themselves but do wear out (hence the "replace" window).

 

We have a 100kA SPD on our incoming supply where it enters the house, then smaller 60kA units on the feeds to the solar on the car port. Delicate or expensive technology gets local good quality, plug-in protectors too.

 

I think you are going to need another box with a nice meaty SPD mounted right next to your incoming MCCB as a start.

If you already had an SPD connected to the system a big surge will destroy it which is what they are designed to do it needs to be replaced, some of them have an indicator to show that its blown, replace with a type 1/2