Question Shock from aerial cable

chris301up

Active Member
Whilst in the current lockdown situation I've finally got around to mounting a new TV I purchased just before Christmas on the wall. Today I finished the power cable installation together with the coaxial cable and HDMI extension cable.

I have had to cut the plasterboard around the noggins to allow the cables to pass through and, before repairing and replastering the wall I just thought that I would test all connections beforehand.

Everything went well until I temporarily connected the new coaxial cable to the existing aerial socket when I had an electric shock. Just to explain in a little more detail. I have installed a new coaxial wall plate outlet behind the TV and the coaxial from this I plugged into the existing outlet. I then used a short coaxial connection from the TV to the new wall outlet socket. Hope this makes sense?

Anyway, surely there shouldn't be any power running through the coaxial cables, or am I mistaken?
 
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mikej

Well-known Member
Mast-head amps require power (usually 5V or 12V) and this is often passed up the coax for convenience from a device like a PVR or a separate power supply, often located in the lounge but possibly elsewhere. Might be worth investigating the aerial or loft to see if that could be a cause ?
 

chris301up

Active Member
Thanks for the reply. I checked the aerial layout yesterday and can confirm that the aerial runs directly from the downstairs to the aerial in the loft. There is a 'spliter' fitter at the base of the aerial where a separate coaxial runs down to supply a TV in the first bedroom. Unless there is voltage being generated from the TV in the bedroom? I may try disconnecting this a little later on and check with a multi-meter.
 

mikej

Well-known Member
I'm not aware of TVs providing this facility myself but if a PVR can then I guess it could be possible, so worth a look. ON PVRs that do, there's usually an option to turn it on and off in the setup menu.

When you say there's a 'splitter' in the loft, do you mean a simple (passive) Y-shaped fitting that splits the signal ? Not a powered booster of some kind, presumably ?

I would be very wary of connecting up your new TV until you've got this sorted :D
 

mikej

Well-known Member
This just popped up in my 'similar threads' box...

 

Rodders53

Distinguished Member
This is a common "problem" and probably nothing to worry about.

It's all to do with the (most likely) double insulated TV and lack of proper earth to it... The TV socket outer is floating at a voltage different to the aerial coax screen and this (extremely low current) discharges when connected.


Alternatively, if TV not double-insulated, you had a static charge on you that got earthed through the TV when you connected the metal aerial plug.
 

Rodders53

Distinguished Member
I'm not aware of TVs providing this facility myself but if a PVR can then I guess it could be possible,
Certainly is on some, usually smaller, TVs. I have owned at least one with the feature.
"Antenna Power"

Useful to diagnose / confirm masthead amp psu failure; or when a new occupant arrives in a home where the movers packed the masthead amp psu and took it in error.

But it's not the cause of the OP's shock. ;)
 

JayCee

Distinguished Member
This is a common "problem" and probably nothing to worry about.

It's all to do with the (most likely) double insulated TV and lack of proper earth to it... The TV socket outer is floating at a voltage different to the aerial coax screen and this (extremely low current) discharges when connected.


Alternatively, if TV not double-insulated, you had a static charge on you that got earthed through the TV when you connected the metal aerial plug.
+1 Completely agree.
 

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