[TC2]

We'd like to replace some switches and plastic wallplates in our 1928 home. As with so many things involving old houses, it's rarely easy or straightforward, at least for novices.

On removing the first wallplate - it cover 2 switches - we found the following:

1) metal wallbox mounted to wood (actually looks like 2 single switch boxes mounted side by side)

2) no grounding wires

3) 5 wires coming into the box - 4 old style copper wires with black rubber insulation under cloth-like insulation and one modern copper wire with white insulation

4) the screw terminals of one switch had one of the old style black wires and the modern white wire attached (this switched seemed wired upside down as it was "off" when the switch was up)

5) the other black wire coming to the side of the box for the switch mentioned in 4 simply ends in a wirenut

6) the other switch is wired into the two black wires coming to that side of the wallbox

Our questions are:

Should we wire in the new switches just as the old switches were wired in? We never had any problems with the old switches (noises, shocks, warmth, flickering).

Can we safely use metal wallplates in this situation? If not, is there anything we could do to set up a ground for the switches that would make it safe to use metal wallplates?

Any other advice on the state of this wallbox would be appreciated.

Thank you!

[rwinterton]

Sounds like very old work -- 1950s or earlier.

I guess I would suggest wiring the old switches the same as the new switches. You don't know where the capped wires go, so fooling with it will not get you anywhere. If you knew where the wires went, or if you could run new wires, it might be a different situation.

I would not use a metal wall plate unless you can run a ground to the box. There would always be a possibility that a live wire could get damaged and make contact with the metal box or with the metal plate. If a ground were present, that would cause the circuit breaker to blow, but without a ground, it could present a severe hazard to anyone who might touch the plate.

[TC2]

In fact I was mistaken about the original wallplate as it was under so many layers of paint and as my wife was the one who removed it and trashed it - it was metal, as are most of the other wallplates in the house that are probably covering electrical work of the same vintage as that described above.

Thanks for the response. Any thoughts on how to ground the switches and/or the box?

My only idea is to attach a metal plate to wooden lathing or a stud near the box (but so the plate doesn't touch the box, or anything else that's metal) and run a wire from the switch's grounding terminal to the plate. But I'm a complete novice - do I need to ground both of the switches and the box, or only the box? Would I need 3 separate (not touching) grounds to cover the 2 switches and the box?

Mother-in-law and wife desperate for new metal wall plates!

[rwinterton]

I believe that bringing it up to code would require removing the walls and running new wires with a contained ground to all of the boxes in the house. I'm not sure what's legal insofar as grounding boxes of your vintage.

There are some green grounding clips that can attach to a metal box. There are also some grounding screws that screw into threaded holes at the bottom of most metal boxes. If you could run a single copper wire through the walls into the box, I'd suggest bonding it to the box using one of these two means. I'm rather doubt that it meets code, but it's still safer than not having a grounded box.

Instead of a plate, I'd suggest running wires from your switch boxes to an electrical box in a single location. You would bond the wires together and crimp a grounding crimp onto them. You should then run a wire from that group of wires to the neutral panel in the breaker/fuse box. I think that even in work as old as yours, that the panel would still be grounded.

In the past, if the box were metal, they didn't require you to take the grounding wire to the switch. They considered the switch to be grounded by the screws. However, that's changed. Code does require that both the box be grounded and the switch or outlet be grounded using a grounded wire bonded with a screw or a clip.

If you can't get it to the circuit panel, then use a grounding clamp to bond it to a cold water pipe -- and make sure that there is a conductive path around any water meters so that the pipe goes through the ground.

Like I said, this definitely isn't going to follow the National Electrical Code, and the law states that if you upgrade, you have to bring it up to code. So, I guess this is a disclaimer. If you do any of this, you do it at your own risk.