Lightning & Surge Protection; What is Mandatory?

It’s all very confusing when it comes to trying to work out what’s mandatory and what’s a recommendation when it comes to lightning & surge protection. This week in our fortnightly blog we decided to try and make it all a bit clearer for you.

What is mandatory?


Lightning Protection

Lightning protection is mandatory in certain circumstances;

  • If the building has external lightning protection already installed (copper tape and earth rods)
  • If the building is fed by overhead power lines


  • When external lightning protection is fitted: When lightning hits the external protection it travels down the copper tape to where it will be cross bonded to your incoming panel, where it connects with the earth. The reason for the mandatory requirement of lighting protection, is that only 50% of the lighting impulse will go directly to earth, the other 50% will travel through the cross bond on to the incoming panel and out on to the electrical circuits in the installation. This creates a massive risk to the life and to the property in this installation.


  • When the building is fed by overhead power lines: When lighting hits the power line, we have the same problem as with the external lightning prooverhead power linestection. The lightning impulse will travel down the power line directly on to the incoming panel, where again it will travel out on to the electrical circuits in the installation.

It is more common to see church’s, schools and hospitals with external lightning protection fitted, as these are classed as high risk buildings, especially with them being public places and in most instances tall. It is less common to see domestic dwellings with external lightning protection, however it does happen occasionally. It is more common to see a domestic dwelling with overhead power lines feeding the property.

Surge Protection

Surge Protection, as in type 2 and 3, are not mandatory, although they are strongly recommended it is not a requirement to have them fitted and your electrical system will still come up to standard without them. In our last blog we discussed the reasons why you would want to fit surge protection in your own home.

I hope this has made it a bit clearer for you, if you need any more advice on what sort of protection you need to be either fitting or recommending, please give us a call on 01484 851747 or you can send us an email through our contact form.

Our website has a great product selector page, to find out which device you need please click here.

Thanks for reading, Helen Johnson

Why should you fit a surge arrester in your home?

Domestic surge arrestors are not mandatory, so why are so many people now fitting them?

The reason is money. The cost of a domestic surge arrestor such as our SY2-D is negligible compared with buying a new TV or replacing the electrical items in your house. Do a quick mental calculation of how much your electrical items are worth, your TV, washing machine, cooker, fridge and not forgetting all of the things you plug in to charge, such as phones, tablets and laptops. Now you can see how that bill would quickly mount up if your home was effected by surges.

Surges occur in every electrical system, they can come from your mains power, turning lights on or turning on large electrical items (such as a washing machine). Unlike lightning damage, Surge damage isn’t as easily seen, it won’t be anything dramatic like blowing up or setting on fire as can occur with lightning damage. Surges just slowly degrade all of the electrical components in your electrical system, which will shorten the life span of your electrical items. A TV that should last 5 years could only potentially last 2 years, if it’s seeing continuous surges.

trailing lead surge protection

Many people say “I don’t need to worry about surges, I use those surge protection trailing leads”. The problem with using these trailing leads as your only form of surge protection is that you don’t plug everything in to them, even the most safety conscious person would not think of plugging their washing machine or fridge through a trailing lead. When you start looking at how many of these trailing leads you would need to protect your whole house, can you imagine how much that would cost? Obviously it would be less than replacing all of your electrical goods, but still expensive, especially when you consider that the majority of surge protection trailing leads sold have little or no information on how they actually work or whether they comply with any sort of standards or regulations.


The most efficient and cost effective way to protect a domestic property from surges is a domestic surge arrester. This can be mounted inside (or next to) any consumer unit, its easily wired in with a parallel connection to an adjacent breaker, a connection to the neutral bar and a connection to the earth bar and that’s it, your whole installation is protected from surge’s.

At only £56.44 each nett, the SY2-D provide a complete surge protection solution to your domestic installation for a great price!

For more information on this device, please see below:

For help choosing the best device if you are looking for something different, please see below:


Thanks for taking the time to read this article and if there is anything you need please contact us on 01484851747.

Helen Johnson

New Product!!! Type 1+2+3, 100kA, Full mode protection common and differential

We have added a new product to our range that directly competes with the Furse ESP415M1. This new product provides enhanced protection to BSEN62305 & BSEN61643. The technical specs are listed below…

  • Very low let through voltage between all conductors less than 600V
  • Full mode protection, phase to earth, phase to neutral, neutral to earth
  • Combined arrester Type 1+2+3 can handle lightning currents and protect sensitive electronic equipment
  • Lightning protection Level 1, which is the highest 100kA 10/350µs
  • Three way visual indication of status
  • Remote changeover contacts can be linked to BMS, buzzer, light etc
  • No earth leakage, means RCD, RCCB will not trip
  • Will extinguish follow currents after activation
  • Din rail mountable
  • Manufactured in Europe by market leading company
  • Can be supplied in a metal or polycarbonate IP65 housing for a small additional cost
  • Internal thermal disconnector

Available in three phase: 10811LED or single phase 10812LED.

Surge Protection Devices Ltd are always striving to bring out new, innovative products to add to their collection of over 3,000 products they already have.

If you would like any more information about this product, please contact our technical helpline on 01484851747.

Come and see us at Elex Exhibitions 2016


It was lovely to see so many familiar faces at the Elex Exhibitions last year. We will be exhibiting again this year at Exeter on 21st and 22nd April, at Harrogate on 23rd and 24th June and at Sandown park on 3rd and 4th November. So pop along to our stand and say hi. The first 10 people onto our stand each day will recieve a FREE domestic Surge arrester worth over £70!

New metal enclosures now available

We can now supply your favourite products in metal enclosures.

New website now live!

It’s been long overdue but I hope you’ll agree that our new website looks fantastic. There are new sections on how to choose a Surge Protection Device, a News & Events section and an updated project list. You can now also shop direct from our website!