I have a Stromberg Carlson Rochester radiogram, which runs the standard 2 core flex (figure 8) mains cable, and requires a separate earth wire to get any radio signal (along with the aerial).
Can I simply run 3 core flex to the unit and earth to the chassis trough the mains, without causing any problems?

I'm familiar with some old sets having a live chassis, but am sure I have had this unit running while the chassis was out (dial cords and small children don't mix) without getting any form of high voltage shocks.

Thanks!

Hi, Does the radiogram have a connection point for an earth connection, a wire or a terminal?

There are two issues,
The first issue and most important is one of safety, you have already mentioned the dangers of a live chassis, you can reasonably safely say that the chassis is isolated from the mains voltage if the set has a power transformer, you can still caught out if it is an autotransformer.

The second issue is, if you can earth the chassis using the household electrical earth how effective will it be? The earth lead in the mains wiring is a long wire that runs back to a busbar in the switch board, most radio earths are expected to be the shortest connection to a copper stake buried in the ground.

If you have a multimeter you could try to measure the resistance between active and the chassis and neutral and the chassis, this should be open circuit.

I havent seen this model, do you have a schemaic? If not, have you got any model information that I can use to track down a schematic.

Failing that maybe photos of the mains wiring and the transformer.

Regards,
Marc

Thanks Marc!
I can either get the multimeter out and check the resistances as suggested, or do it the old fashioned way, and turn the set on and touch the chassis and see if I get zapped (Don't laugh, it works).
The only model info I could find is the model name of Rochester, but I will have another look.
The set does have a separate earth point on the back of the cabinet, and it's not overly difficult to run a wire to an existing earth stake at the front wall of my house. I have in the past seen an old lady run it to a flower pot in her loungeroom and complain it didn't work very well.
I got a great laugh out of that one, but not in front of the old dear.

I can either get the multimeter out and check the resistances as suggested, or do it the old fashioned way, and turn the set on and touch the chassis and see if I get zapped (Don't laugh, it works).

I don't recommend the latter - it may work too well. Using the multimeter is a much better option.