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Earthing and the radio amateur

Stewart Mason
I've recently joined the IET forums. I replied to a  topic regarding amateur radio and PME on the old forum. Unfortunately I cant access the old forum anymore so I thought it would be best to start a new topic.


So. On the bench there is a transceiver with a metal case. Next to the transceiver there is a antenna tuning unit which is connected to a antenna system which is using an earth rod. Am I right in saying there is a chance of a potential difference between the two metal cases of the equipment regardless if it is a TT, TNS or TNCS?


What would be the ideal solution?  Put the shack on it's own TT supply and bond all the radio equipment back to the MET of the TT and if a earth rod is used for the antennas connect that back to the MET also?


If the TT system was not an option what would be best if the supply was a PME and you didn't want to use balanced antennas removing the use of an earth rod? 


To be honest I've never really given PME's and amateur radio much thought which in hindsight was probably a mistake. I do remember when I did my training an earth rod was recommended for the radios.


Apologies for being so random.


Stewart M0SDM
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  • 0
    If your central heating has metal pipework, and there is no bonding in the property between the station earth bar and the PME system, you can expect a touch voltage between the earthing system of the station and the radiator. This voltage can be anything from a few Volts, to perhaps 10s of Volts, and is a result of diverted neutral currents in the PME supply. Certainly on occasion, the voltage could be enough to be felt, and potentially enough to cause a serious electric shock for children or persons with some medical conditions, especially if they are hot and sweaty and there is a large contact area.



    If there is an electrical fault in your installation, or a broken Neutral of the PME supply, the voltage can become hazardous - in the latter instance, perhaps for some considerable time.


    The same is true of any metalwork connected to the protective earthing in the main house installation - such as metal plate switches, etc., and fixing screws of accessories - and of course anything connected to the protective earth of the primary side of your isolating transformer.


    In practice, two things could be done about the radiator:
    • Wooden radiator cover, and remove the antenna connection when you need to clean or work on the radiator.

    • Fit plastic sections of pipework in the feed and return from the radiator


    Everything else - cover up with insulation or replace with a non-conducting equivalent product - or move out of reach
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  • 0
    If your central heating has metal pipework, and there is no bonding in the property between the station earth bar and the PME system, you can expect a touch voltage between the earthing system of the station and the radiator. This voltage can be anything from a few Volts, to perhaps 10s of Volts, and is a result of diverted neutral currents in the PME supply. Certainly on occasion, the voltage could be enough to be felt, and potentially enough to cause a serious electric shock for children or persons with some medical conditions, especially if they are hot and sweaty and there is a large contact area.



    If there is an electrical fault in your installation, or a broken Neutral of the PME supply, the voltage can become hazardous - in the latter instance, perhaps for some considerable time.


    The same is true of any metalwork connected to the protective earthing in the main house installation - such as metal plate switches, etc., and fixing screws of accessories - and of course anything connected to the protective earth of the primary side of your isolating transformer.


    In practice, two things could be done about the radiator:
    • Wooden radiator cover, and remove the antenna connection when you need to clean or work on the radiator.

    • Fit plastic sections of pipework in the feed and return from the radiator


    Everything else - cover up with insulation or replace with a non-conducting equivalent product - or move out of reach
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