Surge protection devices (SPD)

[mattg4321]

Hi guys, hopefully someones going to be able to point me in the right direction here.

We do a lot of work for a small retirement home locally that has recently decided to fit lightning protection. We've pretty much been strong armed into fitting SPD's on behalf of the lightning firm (LF). Being honest I don't have a great deal of experience with them and tried to sidestep the job. No such luck!

The lightning firm(LF) are supplying SPD's, but have supplied little further information. What they have provided seems inconsistent and vague. IMO they don't really seem to 100% know what they are talking about.

1.We have a 3 phase SPD to be fitted at the main intake position. There is a 3 phase DB here, but it has no spare ways. LF have said we need to split the tails and fit a 3 phase switchfuse isolator before connecting to SPD in adjacent enclosure.

2.We have 2x SWA cables running external around the building which we are told need SPD's at the load end. These supply a 3 phase washing machine and a 3 phase cooker (20A each). LF have been pretty vague here and sometimes use the word 'isolator' and sometimes 'switchfuse' and don't appear to know the difference. They want us to cut into the SWA before the existing appliance isolator and fit a 63A switchfuse (or isolator - who knows). This would isolate the SPD.

I'm not sure why 63A has been specified?

I'm not sure if I need to fit a switchfuse or an isolator? I'm not even sure what would stop someone turning it off by accident?

If I cut into the SWA at the load end I'm going to need to double up the cables in the supply side of the isolator - doesn't seem like the greatest design?

Can anybody offer some help/point me in the right direction here. I don't like just blindly following instructions that don't make sense to me.

Cheers

 

[mattg4321]

This is the product to be supplied

https://library.e.abb.com/public/d3e03f037f6b49558c66c5ba81181465/ESP 415 --- Series.pdf

 

[Pete999]

Hi guys, hopefully someones going to be able to point me in the right direction here.

We do a lot of work for a small retirement home locally that has recently decided to fit lightning protection. We've pretty much been strong armed into fitting SPD's on behalf of the lightning firm (LF). Being honest I don't have a great deal of experience with them and tried to sidestep the job. No such luck!

The lightning firm(LF) are supplying SPD's, but have supplied little further information. What they have provided seems inconsistent and vague. IMO they don't really seem to 100% know what they are talking about.

1.We have a 3 phase SPD to be fitted at the main intake position. There is a 3 phase DB here, but it has no spare ways. LF have said we need to split the tails and fit a 3 phase switchfuse isolator before connecting to SPD in adjacent enclosure.

2.We have 2x SWA cables running external around the building which we are told need SPD's at the load end. These supply a 3 phase washing machine and a 3 phase cooker (20A each). LF have been pretty vague here and sometimes use the word 'isolator' and sometimes 'switchfuse' and don't appear to know the difference. They want us to cut into the SWA before the existing appliance isolator and fit a 63A switchfuse (or isolator - who knows). This would isolate the SPD.

I'm not sure why 63A has been specified?

I'm not sure if I need to fit a switchfuse or an isolator? I'm not even sure what would stop someone turning it off by accident?

If I cut into the SWA at the load end I'm going to need to double up the cables in the supply side of the isolator - doesn't seem like the greatest design?

Can anybody offer some help/point me in the right direction here. I don't like just blindly following instructions that don't make sense to me.

Cheers

Install an SPD at the intake position would be my guess, you're after chopping the supply during a lightening strike the intake seems to be the logical point to do this, I'll bow to expert explanation.

 

[Toneyz]

Only fitted them off Eaton MCCB pane3l boards off spare way close to the main switch.

 

[Pete999]

When I fitted SPDs it was a requirement to fit them prior to any loads to prevent damage

 

[mattg4321]

I need to fit one at main intake, but also at load end of externally run cables - incase of a lightning strike affecting these.

 

[westward10]

Is there a main protective bond to the lightning protection, this is essential to lessen the chances of a strike jumping through the wall to the electrical system cpcs.

 

[Strima]

Why have they suddenly decided to fit LP? The likelihood of a building strike in the UK is pretty slim, there is a greater risk of induced current travelling down the supply from other locations.

By adding LP to the building they could be increasing the risk of a strike as it gives a good path to earth. Are they also informing home and business owners in the local area of this installation as this also increases their risk of damage through an indirect strike.

 

[westward10]

Adding lightning protection to a structure has absolutely no effect on increasing the probability of a strike.

 

[mattg4321]

Is there a main protective bond to the lightning protection, this is essential to lessen the chances of a strike jumping through the wall to the electrical system cpcs.

I don't know the answer to this. I have just been asked to carry out the works I detailed above. To be honest I'd rather sidestep it, but that's not really an option. I could just fit what they've told me to fit but I'd like to know I'm doing the right thing.

Any ideas on the above WW10?

 

[westward10]

If you are going to do these works a main protective bond will be required.

 

[westward10]

You normally fit a type 1 or 2 LPD at the source of supply however these are not guaranteed to protect individual items of sensitive equipment. It sounds like they have decided that certain appliances may require further localised protection with maybe a type 3 device but personally I would not have thought a cooker and washing machine would justify this.

 

[mattg4321]

Any thoughts on switchless/isolators anyone? Also why 63A?

 

[westward10]

Just reread your opening post and this could have something to do with the cables being external to the building fabric. Have you spoken to the people who have recommended this.

 

[mattg4321]

I have, they keep dodging the questions! I get the impression they don't really know why they are speccing what they are

 

[PEG]

Adding lightning protection to a structure has absolutely no effect on increasing the probability of a strike.

But it does,because of the very fact you are generating a deliberate and attractive point,for that ionisation to occur.

Two identical structures,close together,with one having LP,which one has the increased chance of being the target?

It is surely the reason why the lone golfer is the thunderstorms first victim

 

[westward10]

It makes no difference.

 

[Wilko]

Just for fun - I've seen this effect several times - lightning appears to have bypassed the tower top protection and smacked at some other place. My take is we can try to control Nature, but sometimes she just lets us know who's in charge .

 

[westward10]

Lightning strikes are not governed by the height of things or what they are constructed of. Lightning protection is not there to attract it but to divert it from the structure if it does strike. Why would you want to attract it!!

 

[DPG]

Lightning strikes are not governed by the height of things or what they are constructed of. Lightning protection is not there to attract it but to divert it from the structure if it does strike. Why would you want to attract it!!

Really?