Murray Safety Switch

I came across a 30 amp/125 Volt “Murray Safety Switch” in an older home today (see pics)…house built ~1927. This is the first I have seen this model of device and was looking for any expert advice (were these used as the homes main service panel back in the day?). The home does have an upgraded electrical service panel (200 amp service with circuit breakers) at the rear of the structure that appear to be servicing the entire home. However, when I did a quick check of the wiring using a voltage pen detector, it indicated live wiring entering/exiting the switch…which confused me. Based on the live wiring entering/exiting the switch, I recommend further evaluation by a licensed electrician. Any thoughts/suggestions?

Thanks in advance.


If it makes you feel better it is the frst time in my life Im seeing a switch like that. This is coming from a person who has seen many. The white boxes on the side and extra cables are a mystery to me as well.

Did you test just the frame or the actual wires inside? If the outside frame lit up a pen tester it could be from a lack of grounding.

Its safe to say that switch is still being used for something but I haven’t the slightest clue what for. Deferring to an electrician wouldn’t hurt in this case.

It was probably the main shut off when the house was new.
That it has power probably means it is being fed by the new panel, those white porcelain thingies at the side were likely for the original knob and tube, but from your pic it looks as if the knob and tube wiring at the switch has been replaced with something different a long time ago, and possibly knock out holes with connectors were installed.
It would probably be safe to say that the modified switch is not UL approved and that an electrician should look at it and possibly search for live knob and tube.

Thanks for the inputs. I did recommend a licensed electrician evaluate the Murray Safety Switch and associated wiring.