This is a general interest/survey type question. Lots of discussions have been had about polarized vs non-polarized line cords, safety caps, replacing old paper electrolytics and paper capacitors, etc. That I full support and understand.

Here's the two questions:

1. Has anyone put together a "box" with GFI and/or breaker/fuse for an old tube radio to plug into and then plug into the wall?

2. What other "new" safety measures have you taken, like possibly fusing the output/high voltage plate supply?

I respect the varied opinions and experiences of all the ARF members. What I am most interested in getting going in a discussion thread are practical solutions that have worked or not worked and why.

Let the sparks fly.....

Thanks,

Mike

The only additional protection I would consider installing is a line-fuse under the chassis.

In general, I don't see circuit breakers, GFCIs, etc as being a substitute for using good wiring materials and practices when I do a restoration.

Whenever I get old radio or test gear in I measure what the leakage is
line to chassis. It isn't easy without the Sencore Powerite..

The second thing for incoming gear is to measure line current and wattage.

Whenever I take old gear out to demonstrate, it is plugged into a portable
GFI which then is plugged into the 120 volt outlet.

Mike, I did exactly that 3 or 4 years ago and use much more than ever expected... for several different purposes.
The photo below shows the unit - a pair of plastic electrical boxes, one upside down, the other right side up. An old hairdryer cord with built-in GFI provides the power. Then power goes to a panel type fuse holder that makes putting in an appropriate fuse (say 1 amp or less) very easy. The two sockets are independent of each other, one has the GFI and fuse, only. The other socket has the GFI, fuse and CL-90 inrush current limiter. Note: the ground pin on the sockets is NOT used - could not fine a two bladed socket.

One way I use this device is to check "as-received" radios. (together with isolation transformer and Variac).

When working on or aligning an operating set, I'll have this device in line after the isolation transformer for that fuse protection.



Robert H.

A GFCI doesn't work with 2-wire devices. It's designed to detect a unbalanced flow to ground and the difference between the hot and neutral lines. I don't think you'll find 3 wire radios before the 70's if then. And as much as one is tempted, don't chassis ground old radios. It won't do anything with wall warts unless the transformer is internally grounded to the ground pin and the defect is in the transformer. Safety wise it's still better with a isolation transformer.

That's not exactly true. Most GFCIs will work on two conductor devices. Some of the receptacle gfcis need a ground but there are portable gfcis and others that don't need a ground to work. They measure the supply line and the compare to the return line and if they differ by .006 amps or more they cut off. They don't care if the lost power is going out thru the circuit ground or thru your body into a water pipe.

In the block marked RECEPTACLE the third paragraph. http://www.cpsc.gov/cpscpub/pubs/099.pdf

Follow the neutral and ground back to the power panel in your home and see where each is bonded.
HINT: It's ground.

Thanks,

Mike

Let's clear the smoke: GFIs DO NOT need a ground to function properly. They're neither designed to or intended to work with a ground. As many know, they sense current differential between both current-carrying conductors- not ground.

Regarding ground and neutral and bonding at the panel: again, this does NOT constitute equivalent conductors; neutral is the only conductor carrying current UNLESS a fault condition exists carrying current through the ground wire. This gets trickier when talking 220 and sub-panels but that is easily explained, too.

Sam

OK. Let's clear the smoke.

The device is a GFCI, as in Ground Fault Circuit Interrupter, not a GFI.

1. Has anyone put together a "box" with GFI and/or breaker/fuse for an old tube radio to plug into and then plug into the wall?

No, these can be purchased from industrial suppliers.

2. What other "new" safety measures have you taken, like possibly fusing the output/high voltage plate supply?

I, generally, install a B- fuse on transformer powered sets using in-line fuse-holders so there is no permanent modification to the chassis...

YMMV

Actually, it's either- which you'll find if you're willing to do a bit of digging. More correctly, they are termed "Residual-Current Devices"- but this is nothing but pedantic drivel: the point IS, they do not require a functioning grounding system to perform their designed function.

My concern was for the safety of the individual's discussing this and the possible misunderstanding by some regarding the function of GFIs. My apologies if your concern over what you feel to be the correct terminology (and I stress that this only what you feel to be correct- although not necessarily so) transcends the need for an accurate understanding of an important safety matter.

I'll try and do better next time, I really will.

Sam