What is EMC testing and why is it important?

If you manufacture electronics, it doesn’t matter whether it is an electric shaver or a computer, before being able to bring it to market there are several tests that it has to pass. In defence, one of the more common of these tests is EMC which checks on how the equipment interacts or interferes with other electronics. The importance of EMC testing varies depending on the product and the industry, with each having different guidelines and standards that they must meet.


Electromagnetic Compatibility, also known as EMC, is the interaction of electronic equipment with both the electromagnetic environment and with other equipment. All electronic devices have the potential to emit electromagnetic fields. With the proliferation of electronic devices into everyday life – TVs, washing machines, electronic ignitions, traffic lights, mobile phones, ATMs, anti-theft tags, to name but a few, there is huge potential for devices to interfere with each other.

EMC Testing is simply that. It is a test or series of tests that are carried out to see how an electrical product interacts with other electrical devices. These tests are performed at different stages of typical use to find where, if any, potential spikes may occur (i.e. switching a device on or turning it off). This interference is then noted and further tests are performed.

As we briefly stated earlier, each product will need to meet specific EMC levels before it can be released to the market and sold. These levels vary and are dependent on the general guidelines and rules set out by different governments across the world. GRiD is based in the UK so we’ll use the UK government’s rules. The UK airs on the more stringent side with laws introduced in 1992 that require all manufacturers and importers of electronic goods to ensure that their products are electromagnetically compatible, with most manufacturers opting to place ‘CE’ marking on their products as a signal that they comply with UK law.

As GRiD work to military specifications, all of our hardware is built to both MIL-STD-461 and DEF STAN 59-411. By ensuring that we meet both of these strict requirements it enables our products to be used the world over in a variety of applications and allows us to deploy our hardware on programmes within naval vessels, aircraft and battlefields.


EMC testing is important for a couple of reasons. Firstly, you want to make sure that any electrical product that you produce isn’t going to interfere and cause issues with other electrical products in its vicinity (emissions). Not only could that damage your product (and your company’s reputation) but it runs the risk of damaging or at the very least, hindering other electronics it is near. As a very clear example of this, if you were to take a mobile phone that had a very high EMC profile onto a plane, the likelihood of it interfering with the plane’s electronics and equipment is very high, possibly leading to unnecessary issues. As a side note, this is one of the reasons why you are asked to put phones into ‘Airplane Mode’ or turn them off entirely when flying so that the risk of interference is reduced as much as possible.

Another reason is that you want to ensure your product is not affected by interference from other electrical devices (susceptibility). You are not in control of the equipment used alongside yours and therefore your equipment needs to be designed so to not be affected by noisy equipment. It needs to be protected from electromagnetic emissions either radiated from a device or conducted from a cable linking the equipment.

From GRiD’s perspective, because we build our products for use around a lot of high tech and often very sensitive equipment, we ensure that any ‘noise’ produced by our hardware is as low as possible so that any surrounding equipment is not affected. Due to our operations within the defence industry, we have to go one step further and deal with the unique situation of the risk of surveillance. If one of our products were to give off a lot of noise or interference, it could be picked up by unwanted persons which could, in turn, endanger lives and ruin field missions so we build our equipment in such a way that this cannot happen.


As EMC testing and safety for use in the field are very high priorities for us, we use proven design methods copied across the range of GRiD products such as filtering, sealing design and shielding. This ensures that our pass rate when going into formal qualification is very high. This coupled with over 30 years of EMC Design experience makes for a very quiet and reliable product. We also spend significant time in Test Chambers working on filtering and proving any new concepts introduced. In fact, we often wonder if we spend more time in EMC Test Chambers than we do in the office!

If you are interested in learning more about EMC testing or would like a demo of our products in action then give us a call on +44 (0)1628 810 230 or email one the team at sales@griduk.com and someone will happily help you out.