To Surge protect or not Surge protect that is the Question!

[spud1]

Hi,

A wholesaler tried to tell me that Surge protection is now a requirement in DBs under 18th Regs today. Im pretty sure thats rubbish but just wanted to put it out there. I know alots been added on SP in the new Regs but Im pretty sure its still only risk assessment driven and not a requirement in a single dwelling where cost out ways potential loss. They also tried telling me that surge protection from lightning is required, but I'm fairly sure that theres a probability calc for lightning (if anyone can remind me of it that would be great!) that I did on a design course a few years ago that proved that lightning in this country wasn't frequent enough to warrant a 'SP protection needed' outcome of the calc.

Cheers chaps

Spud

 

[Pete999]

Hi,

A wholesaler tried to tell me that Surge protection is now a requirement in DBs under 18th Regs today. Im pretty sure thats rubbish but just wanted to put it out there. I know alots been added on SP in the new Regs but Im pretty sure its still only risk assessment driven and not a requirement in a single dwelling where cost out ways potential loss. They also tried telling me that surge protection from lightning is required, but I'm fairly sure that theres a probability calc for lightning (if anyone can remind me of it that would be great!) that I did on a design course a few years ago that proved that lightning in this country wasn't frequent enough to warrant a 'SP protection needed' outcome of the calc.

Cheers chaps

Spud

Trying it on Spud trying to up his profits

 

[SparkyChick]

I believe there is an exemption you can use for single household domestic properties, but that aside you either fit it or carry out a risk assessment and make a decision based on that.

 

[SparkyChick]

443.4 Overvoltage Control

Protection against transient overvoltages shall be provided where the consequence caused by overvoltage could:

(i) result in serious injury to, or loss of, human life, or
(ii) result in interruption of public services and/or damage to cultural heritage, or
(iii) result in interruption of commercial or industrial activity, or
(iv) affect a large number of co-located individuals.

For all other cases, a risk assessment according to Regulation 443.5 shall be performed in order to determine if protection against transient overvoltages is required. If the risk assessment is not performed, the electrical installation shall be provided with protection against transient overvoltages, except for single dwelling units where the total value of the installation and equipment therein does not justify such protection.

 

[buzzlightyear]

not another trying to sell spuds to another spark , the only time you will put them in if you read the IET regs ,a lot of people are getting confused on the issue .

 

[Pete999]

I believe there is an exemption you can use for single household domestic properties, but that aside you either fit it or carry out a risk assessment and make a decision based on that.

Where Surge protection may not be required
Protection against over voltages of atmospheric origins not required in the following circumstances but the rated withstand voltage of equipment must meet the requirements of Table 443.2 of BS 7671:2018

Where SPD protection is required
Protection against Transient over voltages shall be provided where the consequence caused by over voltage:
a) Results in serious injury to, or loss of life e,g, ( Hospitals , Care homes , home dialysis equipment.
b)results in interruption of public services and/or damage to cultural heritage,e,g (data centers, heritage status buildings like museums and castles)
c) results in interruption of commercial or industrial activity e,g, ( banks, hotels, supermarkets, industrial plants, farms)
d) affect a large number of collocated individuals e,g, ( offices, universities, schools residential tower blocks)

For all other cases than above a risk assessment to determine the Calculated Risk Level CRL shall be conducted to 443.5 (See appendix IET gn 1 for further info)

 

[buzzlightyear]

its a pity that is not a pdf Pete , so some people down load it a posted it in the BBB.

 

[Pete999]

its a pity that is not a pdf Pete , so some people down load it a posted it in the BBB.

It's in the OSG Buzz.

 

[Pete999]

its a pity that is not a pdf Pete , so some people down load it a posted it in the BBB.

There is a paragraph missing in my post where did it go?

 

[Ian1981]

No CRL risk assessment required for single dwellings, just whether it justifies protection for the equipment Thein ie cost.
If the dwelling has say a life saving machine in it like a dialysis machine or other health/life support equipment for treatment at home, then that could come under indent (i) loss of life so it will most likely be required

 

[buzzlightyear]

It's in the OSG Buzz

page 39, I did not have that to hand .

 

[Pete999]

Where Surge protection may not be required
Protection against over voltages of atmospheric origins not required in the following circumstances but the rated withstand voltage of equipment must meet the requirements of Table 443.2 of BS 7671:2018

Where SPD protection is required
Protection against Transient over voltages shall be provided where the consequence caused by over voltage:
a) Results in serious injury to, or loss of life e,g, ( Hospitals , Care homes , home dialysis equipment.
b)results in interruption of public services and/or damage to cultural heritage,e,g (data centers, heritage status buildings like museums and castles)
c) results in interruption of commercial or industrial activity e,g, ( banks, hotels, supermarkets, industrial plants, farms)
d) affect a large number of collocated individuals e,g, ( offices, universities, schools residential tower blocks)

For all other cases than above a risk assessment to determine the Calculated Risk Level CRL shall be conducted to 443.5 (See appendix IET gn 1 for further info)

The missing bit
Where SPD may not be required
For single dwelling units where the total value of the installation therein, does not justify such protection and the consequential losses are tolerable
To be read as "Where SPDs may not be required"
Page 39 18th edition

 

[buzzlightyear]

No CRL risk assessment required for single dwellings, just whether it justifies protection for the equipment Thein ie cost

would you like a spud in the consumer Mr customer ,just in case THOR the god of thunder and lightening decides to throw a wobbler out side your house .

 

[Pete999]

would you like a spud in the consumer Mr customer ,just in case THOR the god of thunder and lightening decides to throw a wobbler out side your house .

As long as it's a roasted Spud, which it would be if it didn't work

 

[Ian1981]

would you like a spud in the consumer Mr customer ,just in case THOR the god of thunder and lightening decides to throw a wobbler out side your house .

Not so much lightning but transient voltages from the HV network feeding into the LV network.
That and indirect lighting strikes

It’s all a load of -------s isn’t it?

 

[buzzlightyear]

he missing bit
Where SPD may not be required
For single dwelling units where the total value of the installation therein, does not justify such protection and the consequential losses are tolerable
To be read as "Where SPDs may not be required"
Page 39 18th edition

what about the flow chart has well .

 

[Pete999]

what about the flow chart has well .

Yep next page Buzz, all good stuff if you can't sleep.

 

[buzzlightyear]

Not so much lightning but transient voltages from the HV network feeding into the LV network.
That and indirect lighting strikes

or some person steeling the copper wiring .

 

[Pete999]

or some person steeling the copper wiring .

As long as they have a Permit to Work, or should that be Permit to Nick, like a PtoN Number as opposed to a PtoW

 

[Strima]

Can't move for the amount of heavy industrial switching in my area causing transient over voltages...

As for indirect lightning strikes, more chance of the house getting hit than any of the distribution network as it's all underground to the transformers, nearest overhead supply is over a mile away but the total distance the surge would have to travel is nearer four miles via a couple of transformers, a power station and all the surge arrestors on the pylons.