Station grounding.

 

There's an interesting piece, partly about station earthing, over on PE4BAS' blog at the moment.

Whilst I commented on the dangers of misunderstanding earthing, which is widespread, it doesn't seem to have appeared. Bas later said he didn't see the comment.

Well, these things happen.  Given Bas' response, I think it's important to underscore the dangers even more than I had already, so I've updated this blog a little as a result.

What I will place here is a clear warning to anyone who is thinking of attaching (or already has) wires to the earth system of a house.  

UPDATE: this post unexpectedly became even more relevant, as the ARRL merrily published (21/12/2021) a graphic on their FB page that shows a grounding system that would not be acceptable or legal where PME systems exist.  They should know better, not least as PME is used in some parts of the US, and widely outside of the US.  ARRL publications are widely sold outside the US, which only highlights the failure of the ARRL to consider the potential consequences.

Firstly, there are laws about modifying the electrical supply systems, including the earth, in most countries.  These can carry criminal punishments if you don't adhere to them.  Having a radio licence does not make you qualified, nor does it give you consent to start fiddling with the electrical supply, even in your own house.  You may resent being told that, but that doesn't make it any less true.

One, very good reason why these rules exist is because, if you do get things wrong, that error might well appear on the lines outside, putting people working on them in danger.  

Secondly, an RF earth is not the same thing as an electrical safety earth - although under certain fail conditions, they can become the same thing - and run the very real risk of starting a fire. 

In PME systems, for example, the earth is connected at the input to your house at the neutral; one wire serves two functions.  If the neutral breaks, say, in a storm, then you could find your entire neighbourhood's circuit trying to complete to earth via your radio equipment.  It won't take it, by a very long margin, and will catch fire.  Neutral breaks are not exactly rare.  You might be lucky and find there's a drop to ground from the line outside which happens to be in the right place to stop this situation from arising.  But you can never know where any break will be, so you can't sensibly take a gamble on the PME arrangement outside.

A PME system, as widely found in the UK.  If you install RF earths, it is a legal requirement - and, strictly, requires a qualified installer - to connect every one with its own 10sq mm minimum cable back to the 'incoming' earth (which would be at the chocolate block connector in practical terms here).  No advice is given - seek a qualified installer and talk to your network. A point of weakness may remain, even then, because the earth cable that runs from the input fuse to the distribution box is often not of a high enough cross-sectional area.  You can't change this wire (at least, not legally), and so a network engineer will need to do it.

Your electrical supply may be very different in nature, especially in relation to the earthing system, to the person writing about what they've done in the shack.  It's as well to remember this. 

This is a typical 'recommended' earthing system for radio shacks you can find online, often originating in the USA.  In a large part of the UK, this WOULD NOT conform to regulations, and represents a SERIOUS FIRE RISK - which includes burning your house down. A heavy-duty earth cable from the rod, directly back to the supply input earth/neutral is required in common PME systems.  Screw-type connections to the rod should be avoided - they tend to corrode and make bad connections.

Just remember that your house may well burn down if you connect things up wrongly and contrary to electrical rules.  If that happens, an insurance company is almost certain to refuse - quite rightly - to pay out.  That is a very serious and ruinous outcome.  If Bas, or anyone else, is qualified to do such work, then all well and good; my post wasn't aimed at such people, rather obviously, and they shouldn't be offended.  But others should be very careful indeed.

I urge anyone who is thinking about station grounding to consult their network supplier, and seek such information and consent as may be required.  Connecting wires up to copper rods is easy.  Recovering from an uninsured, burned-down house is not.