What Gage Wire in Old radios?

I'm going to be restoring a few old radios from the 30's and have to get some cloth covered wire. Not sure if I should go with the 20 or 18 gauge 600v wire. Any ideas?

Thanks

Since the current is small 20 gage should be acceptable. Just think of it this way. A 18 gage wire can handle about 1,600 watts if it is about 8-12 feet long as an extension cord. So a shorter length will handle even more. There is no way that most radios are designed to use the same amount of current.

Most old radios will use 35-260 watts. No more than an ordinary light bulb. If you used that size wire (20 gage) and it were a foot long you could probably handle the current like that of a portable heater of 4000 watts.

Most current in a radio will be used by the filaments and that could be on the order of 1.5 amps or 15 watts.

This is not precise but ball park figures.

I've seen "repairs" done to 400 volt circuits with light gauge telephone patch panel wire. Not that I recommend you do that, but it should help put things in perspective.

Just make sure the rated voltage is 125v or above.
Telephone wire is rated at about 32v- bad choice.
its the insulation and heat resistance that matters more than the Gage in none critical applications.