Surge protection

[Sparkzz]

Hi,

Has anyone had experience in fitting surge protection when it comes to pv systems? I'm talking about commercial/public use buildings, 3phase systems.
Is there any need to fit surge protection, does the d/c need protected as well as the a/c, is there a preference in fitting type 1 SP, or individually protecting circuits with type 2?

I've not long got back into electrics having been a way for a while, the regs have been updated somewhat. Seems like more hoops to be jumped through

Thanks

S

 

[binky]

why are you thinking of fitting surge protection? Pv shouldn't affect it and I wouldn't start interfering with DC side, most inverters have some form of DC protectin built in.

 

[Sparkzz]

Thank's for the reply binky,

Believe me if not fitting SP is ok I'm good with that. It's just I seem to recall somewhere in the regs about installing new circuits in commercial premises requires SP if certain requirements are met. I'm hoping pv doesn't meet those requirements.

 

[binky]

Thank's for the reply binky,

Believe me if not fitting SP is ok I'm good with that. It's just I seem to recall somewhere in the regs about installing new circuits in commercial premises requires SP if certain requirements are met. I'm hoping pv doesn't meet those requirements.

You are supposed to risk assess the site for lightning strikes, then decide if you need SP. Not sure if that applied to commercial, but I wouldn't be peeing about with it for an odd new cct. It's generally fitted to the incoming tails.

 

[Sparkzz]

You are supposed to risk assess the site for lightning strikes, then decide if you need SP. Not sure if that applied to commercial, but I wouldn't be peeing about with it for an odd new cct. It's generally fitted to the incoming tails.

Yes, I think commercial is different. I'll check the regs out tomorrow. If I can recall, SP needs to be taken into consideration when installing a new circuit into commercial or publicly used premises if it meets certain criteria. The risk assessment I think was to do with domestic properties.

Type 1 SP at the origin
Type 2 @ the circuit.

Like you said, most inverters cover SP for the d/c

 

[Sparkzz]

More info regarding SP and the regs

 

[Sparkzz]

So to me, the above seems to be saying unless you can prove otherwise by means of a risk assessment, over voltage protection needs to be installed?

 

[binky]

So to me, the above seems to be saying unless you can prove otherwise by means of a risk assessment, over voltage protection needs to be installed?

I read that as install where there is a serious risk, not as compulsory.

 

[Sparkzz]

Confusing.

So you got to ask yourself. If there's a chance of transient over voltage which could cause the 4 possible outcomes you would have to instal SP devices. How would you prove this?

If there's no chance of the 4 possible out comes and a risk assessment has been carried out then there's no need to install SP.

But if no risk assessment has been carried out you need to install SP?

 

[binky]

If it's an existing installation that's had no problems doesn't meet those criteria, and you aren't installing anything likely to be an issue, then the risk assessment is met for not needed. I'll go give that section a read before commenting further.

 

[binky]

Confusing.

So you got to ask yourself. If there's a chance of transient over voltage which could cause the 4 possible outcomes you would have to instal SP devices. How would you prove this?

If there's no chance of the 4 possible out comes and a risk assessment has been carried out then there's no need to install SP.

But if no risk assessment has been carried out you need to install SP?

ok, I've given that full section a read. You are suppossed to assess the site for lighting strikes and generate a risk assessment. However as you are adding to an exiting installation, I'm not sure that would be relevent. App 16 shows SPDs as installed at site origin, so if you were installing a new board at origin, then yes, definetly need the RA and act accordingly. What I am not reading is anything that says the RA is required when adding / altering an existing system, although we would add RCD protection if required and absent. @Sidewinder perhaps you can help wth this?

 

[Mike.J]

I read that as the RA is not required for "single dwelling units where the total value of the installation and equipment therein does not justify such protection" you do not need to do a RA or install a SP in a domestic building if you are willing to take the risk.

 

[Sparksfly]

Over the last 15 years Id say there is only one property I have recommended surge protection. This was approx 8 years ago. Extractor fans failing after 2 to 5 days depending on quality.....it was near an industrial site, an area known to dehn for transient voltages. Heavy power hungry plant in use...and I don't mean the leafy green stuff.

 

[Sparksfly]

I mean... how many ads are there plugging spd's including the regs? !!!

 

[Mike.J]

The Dordogne area of France is the lightning capitol of Europe, so I have some experience of Surge Protectors, most I have come across blink out on the first hit and have to be replaced, very expensive on three phase supplied properties, the latest versions seem to be able to take three of four hits (according to severity) before giving up the ghost, most newer version have individual replaceable cartridges, which lessons the blow, but still expensive, I replaced three (nine cartridges) then gave up and just un-plug everything during a storm and when I leave for an extended time.

 

[Richard-the-Ninth]

Just thinking out loud:
Have you ever wondered what an SPD is?
It seems to me (As some are / have a replaceable "cartridge" that have 2 connections) that they are overpriced Metal Oxide Varistors.
FYI these are a resistor with a high resistance at low voltage, as the voltage goes up, the resistance comes down, creating a dead short. This happens faster than you can blink.
I think that SPDs are just an easy way to make "Loads of money"

 

[Mike.J]

I do remember seeing a u-tube vid of someone taking one apart and coming to the same conclusion, some of the cheaper ones he took apart left a lot to be desired in the safety aspect of how they worked, but Governments being what they are they will soon become legislation, driven by industry and as you say and easy way to make "Loads of money"

 

[Geoff1946]

The Dordogne area of France is the lightning capitol of Europe, so I have some experience of Surge Protectors, most I have come across blink out on the first hit and have to be replaced, very expensive on three phase supplied properties, the latest versions seem to be able to take three of four hits (according to severity) before giving up the ghost, most newer version have individual replaceable cartridges, which lessons the blow, but still expensive, I replaced three (nine cartridges) then gave up and just un-plug everything during a storm and when I leave for an extended time.

When you experienced the "hits" did the suppressors save your appliances ?

 

[Mike.J]

When you experienced the "hits" did the suppressors save your appliances ?

No electronic appliances plugged in, I habitually unplug when a storm hits or I leave the premises for an extended period, all the white goods stay plugged in and they all survive with or without the Surge protector.

Additionally due to Covid the place was unoccupied for nearly two years, during that time the Surge Protector would have been hit a sufficient number of times that it would be out of service when the next storm hit, so unplugging things seems the best option.