SPD in commercial offices

I can tell you that the same process should be carried out as for domestic premises, but that’s simply from following the regulations and we’ve already established you’re not keen on that.

To clarify, that’s 443.4 where single dwellings are excepted from the requirements to perform a risk assessment. You need to carry out a risk assessment or if you decide not to carry out a risk assessment you need to provide transient overvoltage protection.

I recently had a similar question. Part of my journey towards the answer in my particular case was this short article:

Can we not turn this thread into a --- for tat argument. Some posts have been removed.

westward10 said:

Can we not turn this thread into a --- for tat argument. Some posts have been removed.

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Fair. Sorry for my part. And sorry to John for the comments.

So what the guidance is saying Johnboy, do a risk assessment of clients electronic equipment (cost)and ask them isit worth it or not.

They should sign it too.

Got caught out on my NIC assessment in 2019 for not fitting them on a commercial job.

Did they make u go back and fit it?

No, just stearnly told us to do risk assessments in future on an individual basis (ie, for the cost and hassle of doing the assessment and getting approval from the client NOT to fit it its just easier to go ahead and fit surge and charge a bit more for the job)

I agree with @Doomed
In many cases if you cost the time to perform the risk assessment and go through the options with your client (including getting the value of equipment they have that is susceptible to damage, and the cost implications of lost business due to damage-induced down-time, etc) it will cost about the same as fitting a type 2 SPD anyway!

Edited to add: If they have a lightning protection system to need type 1 SPD then it has to be fitted anyway. Though some remote sites with lots of lightning activity might be better served with a type 1 so it lasts longer.

What happens if their electronic equipment still goes bang in a lighting storm

i=p/u said:

What happens if their electronic equipment still goes bang in a lighting storm

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Their problem, as you have done your bit.

Most electronics should survive at least the CAT-II sort of surges, but some are simply crap, and others are also vulnerable to damage though data lines (cable TV coax, phone line, etc) so would need separate protection.

You can harden electronic installations to survive a direct hit and keep going, but not domestic installations for sure!

Have other services as phone, cable tv adopted this too?

i=p/u said:

Have other services as phone, cable tv adopted this too?

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Don't know about cable TV, but traditional phone lines always had SPD at the master socket and there are standards for the sort of spikes that telecoms stuff should handle.

Though I suspect that has gone from newer systems. Probably BT, etc, treat the modems as disposable - they often don't update the crap software anyway!

From the archive of "here is one prepared earlier" we installed a system in Italy in 1995 and upgraded its computers and radio part in 2005. In 2019 I went out to repair it as they said it stopped working in one of its frequency bands, but the antenna was still tracking and working in the other.

Only later did they admit that it happened at the same time as a lightning storm.

Then when I got there and took down the front-end (bit that sits at the focus of a dish-style antenna) to replace the failed low-noise amplifier I found this melted spot where it actually had been hit:


Here is a photo of what that metal cover has inside:

We had put some effort in to protecting it against induced lightning surges, but never thought it would have survived a direct hit!

This was not really planned for, and the bureaucracy of trying to get the institute to fit some protection (and find the budget to do so) was a problem. The building itself was protected, but the antenna was now the highest point.

So we made up a makeshift LPS using stuff from local hardware shops, in between ice-creams and coffees, and hopefully it will be OK for the future:

i=p/u said:

What happens if their electronic equipment still goes bang in a lighting storm

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In a commercial set up the installation should be set up in zones, each one designed to step down the surge current to a tolerable level at the equipment.



Same can be applied in domestic by using type 3 surge protected outlets.

pc1966 said:

We had put some effort in to protecting it against induced lightning surges, but never thought it would have survived a direct hit!

This was not really planned for, and the bureaucracy of trying to get the institute to fit some protection (and find the budget to do so) was a problem. The building itself was protected, but the antenna was now the highest point.

So we made up a makeshift LPS using stuff from local hardware shops, in between ice-creams and coffees, and hopefully it will be OK for the future:
View attachment 86202

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Nice idea, I'm surprised they wouldn't just stump up for a couple of finials, they tend to be a lot cheaper than the damaged caused by a strike.

Strima said:

Nice idea, I'm surprised they wouldn't just stump up for a couple of finials, they tend to be a lot cheaper than the damaged caused by a strike.

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Ideally they would have had it done when the building LPS was updated at some point between our original installation and when we had to fix it. We saw the change in conductors, etc, but no thought about a point going above the antenna! There you go

Our make-shift one is not ideal, as it would provide weak protection from some directions as not high enough and no time / spare cash to put in a couple of them. But it was the first direct hit in over 20 years so not that common.

Strima said:

In a commercial set up the installation should be set up in zones, each one designed to step down the surge current to a tolerable level at the equipment.

View attachment 86206

Same can be applied in domestic by using type 3 surge protected outlets.

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I thought if you covered the incommer the rest is just optional.

pc1966 said:

others are also vulnerable to damage though data lines (cable TV coax, phone line, etc) so would need separate protection.

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That has always been my concern. OK SDP may save boiler pcb's and LED lights, but the expensive stuff is still vulnerable via data cables.

i=p/u said:

I thought if you covered the incommer the rest is just optional.

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There is the incomer protection, and a second shield about 30 foot from the incomer. This may be anti-surge sockets on vulnerable equipment.

Strima said:

In a commercial set up the installation should be set up in zones, each one designed to step down the surge current to a tolerable level at the equipment.

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I just looked at John Ward's Youtube vids on SPDs - has series of about five vids on SPDs, emphasising how essential it is. He goes into the zones aspect. Worth looking at.

John-SJW said:

That has always been my concern. OK SDP may save boiler pcb's and LED lights, but the expensive stuff is still vulnerable via data cables.

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It is less common now, as networking is mostly wireless or Ethernet (which is usually isolated and can take kV level spikes) within a building, and usually these days fibre between network switches in different buildings (or sometimes between floors of a building) which is to all intents and purposes immune to surges.

PoE Ethernet is more vulnerable due to the DC path for the power. Also commonly seen is RS232 / RS422 used for industrial plant, but they are often OK if not running hundred or more meters, or (more seriously) between buildings. Well-bonded cable try also helps to divert some of any induced surges away from the signal cables.

Again, not really domestic!

For domestic the risks for surges, outside of the AC power lines, are TV/satellite antennas/CCTV (really only if hit) and cable TV / telephone lines (as they run for long distances outside of the building).

i=p/u said:

So what the guidance is saying Johnboy, do a risk assessment of clients electronic equipment (cost)and ask them isit worth it or not.

They should sign it too.

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Having seen a hospital take a substantial lightning strike with a repair bill of circa £500,000 and about 4 - 5 days disruption there was a full risk assessment done on the future risk of it happening again the results of which concluded that the cost (around £600,000) of installing the necessary protection across the site versus the strike risk was not a viable spend having had no documented strikes in the previous 40 - 50 years and a calculated future strike risk of 1 sometime in the next 44 to 400 years

Doomed said:

Got caught out on my NIC assessment in 2019 for not fitting them on a commercial job.

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Doomed said:

No, just stearnly told us to do risk assessments in future on an individual basis (ie, for the cost and hassle of doing the assessment and getting approval from the client NOT to fit it its just easier to go ahead and fit surge and charge a bit more for the job)

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Sounds like the NIC trying to make a point and help the manufacturers sell more, I'm surprised the NIC are not insisting on professional indemnity for contractors in case they fit the wrong type of SPD

i=p/u said:

What happens if their electronic equipment still goes bang in a lighting storm

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Anyone for efficacy insurance if the SPD fails to operate under surge / strike conditions

pc1966 said:

Don't know about cable TV, but traditional phone lines always had SPD at the master socket and there are standards for the sort of spikes that telecoms stuff should handle.

Though I suspect that has gone from newer systems. Probably BT, etc, treat the modems as disposable - they often don't update the crap software anyway!

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I've seen a lot of surge arrestors fitted on intruder alarm comms kit where the installer didn't bother to connect them to a suitable earth so it made them a bit useless

pc1966 said:

Ideally they would have had it done when the building LPS was updated at some point between our original installation and when we had to fix it. We saw the change in conductors, etc, but no thought about a point going above the antenna! There you go

Our make-shift one is not ideal, as it would provide weak protection from some directions as not high enough and no time / spare cash to put in a couple of them. But it was the first direct hit in over 20 years so not that common.

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I've worked on a number of sites with rooftop comms kit and while installing comms kit I got into the habit of doing a quick test on the LPS down lead after we had some interference problems on one site where all the comms cables going to a number of buildings were earthing the LPS at the indoor units because the LPS down lead connection to the earth rod was broken and this was on an LPS that had been tested and certified some 10 months earlier the customer was adamant that it was ok and waved the certificate at me so I got a spade out and exposed the corroded LPS earth connections and then had to more or less drag him out of his office across the site to show him the problem that we had found

John-SJW said:

I just looked at John Ward's Youtube vids on SPDs - has series of about five vids on SPDs, emphasising how essential it is. He goes into the zones aspect. Worth looking at.

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Based on what risk assessment and likely hood of it actually happening

When you look at the cost of an SPD I suppose it could be classed as an insurance policy that could sit there for many years and may never ever be needed so how do you justify the cost to the customer. As installations are altered and modified should the risk assessment be revisited to confirm that the type of SPD's installed are suitable for what may be a changed risk within the installation or whether the changes mean an SPD should be installed, which is something that no doubt will be addressed in future guidance

The combined industry experience of this forum probably runs to many hundreds if not thousands of years so the question is how many jobs have members been to where SPD's may have or would have prevented equipment damage and then would the cost of installing SPD's v's the replacement / repair cost of the equipment and disruption caused made it a cost effective decision to install SPD's
Personally in all the years I have worked in the industry I have only seen less than a handful of incidents that may have benefited from an SPD being installed so why is the push now to suggest that sites are at a much greater risk