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

spud1 · Jan 17, 2019

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

buzzlightyear · Jan 17, 2019

Pete999 said:
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 · Jan 17, 2019

buzzlightyear said:
what about the flow chart has well .

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

buzzlightyear · Jan 17, 2019

Ian1981 said:
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 · Jan 17, 2019

buzzlightyear said:
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 · Jan 17, 2019

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.

Zdb · Jan 18, 2019

[ElectriciansForums.net] To Surge protect or not Surge protect that is the Question!

Hope this helps

spud1 · Jan 18, 2019

This is all really helpful stuff! Thanks guys (Although I resent them being referred to as Spuds! Haha) One question, perhaps a silly one. How are we supposed to ascertain the length of overhead or underground LV or HV network cables in order to complete the CRL risk assessment equation for Lightning strikes? I've phoned a mate at our local DNO and he doesn't think their maps would be available to mere Sparkies like what we is?

ruston · Jan 18, 2019

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

Save the screen shot to paint , edit then save as a PDF.

Nigel · Jan 18, 2019

spud1 said:
This is all really helpful stuff! Thanks guys (Although I resent them being referred to as Spuds! Haha) One question, perhaps a silly one. How are we supposed to ascertain the length of overhead or underground LV or HV network cables in order to complete the CRL risk assessment equation for Lightning strikes? I've phoned a mate at our local DNO and he doesn't think their maps would be available to mere Sparkies like what we is?

That scenario is covered in BS7671 and gives you a guide of I think 1000M. If you have to use the estimate distance in BS 7671 it is always going to direct you to install SPDs.

spud1 · Jan 18, 2019

essex said:
That scenario is covered in BS7671 and gives you a guide of I think 1000M. If you have to use the estimate distance in BS 7671 it is always going to direct you to install SPDs.

Could you direct me to that scenario in BS7671 please essex?

Nigel · Jan 18, 2019

spud1 said:
Could you direct me to that scenario in BS7671 please essex?

Will have a look later. It is in the risk assessment part.

spud1 · Jan 18, 2019

essex said:
Will have a look later. It is in the risk assessment part.

Thanks V much, Ill try and have a look myself in the meantime, if I ever finish these certificates!

richy3333 · Jan 18, 2019

Didn't the bod who did the talk FOR the NICEIC (he's not NIC himself) say the financial cost was to be... either £1000 or £1500. If the risk of damage is over that in a domestic situation you have to fit a SPD?

Pete999 · Jan 18, 2019

richy3333 said:
Didn't the bod who did the talk FOR the NICEIC (he's not NIC himself) say the financial cost was to be... either £1000 or £1500. If the risk of damage is over that in a domestic situation you have to fit a SPD?

Don't know Richy, but I bet he was paid by the NICEIC.

spud1 · Jan 18, 2019

richy3333 said:
Didn't the bod who did the talk FOR the NICEIC (he's not NIC himself) say the financial cost was to be... either £1000 or £1500. If the risk of damage is over that in a domestic situation you have to fit a SPD?

Thats gotta be most houses, considering TVs, set top boxes, gadgets on charge, kitchen appliances etc etc etc. Wonder who came up with that figure?

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

spud1

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buzzlightyear

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Pete999

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buzzlightyear

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Pete999

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Strima

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Zdb

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spud1

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ruston

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Nigel

spud1

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Nigel

spud1

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richy3333

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Pete999

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spud1

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