Why are there two hot wires on the same terminal screw?

(2011-02-06 15:21:26) 1. James Johns Says: There are a total of three hot wires on this light switch, the ground wire is just sort of draped over the metal on the switch. It looks like the hot wires are coming in from the main and going out in two other directions. But Im pretty sure your not suppose to screw two under one screw. Should I just pigtail either one of the two and link that to one screw and leave the other screw like it is? Or does it matter which screw the main comes into and the other hot leads out of?2. Motorhead Says: More information would be really helpful, such as what year, make, and model car you are referring to.

But I also wonder what you mean by hot wire?
Normally there is only 1 hot wire in to a light switch, and it then goes out to all the rest depending on switch position.
Normally a switch gets no ground at all.

But your question would make a lot more sense if you were referring to house wiring.
In that case, one usually uses one switch as the hot input junction to the next device, as well as output to the lamp. But yes, with 110 volt wiring you should not try to hook more than one wire around a terminal screw. So yes, the best thing to do is to join the 2 black power wires together with a third short pigtail that you then put to the switch. Use a red screw connector that can hold all 3 wires. The whites neutral should then also have 3 wires connected; the one from the box, the one to the lamp you want to switch on and off, and the one leading out to the next device you want to power and switch.3. Motorhead Says: With romex the boxes don't matter much, but the green third wire should be screwed to the metal if each device and also carefully continued along the chain to the next device as well. This will ensure no device can ever give anyone a shock, even if they short internally. 4. Timbo is here Says: You have a ring main system. Complicated compared to the way they are done now and it does mean that sometimes more than one wire goes to a terminal - not a problem according to my mate who is a fully qualified spark and does my stuff. I get him round as he understands this ring main stuff where I don't totally get it.5. suzonka Says: In wiring yes its possible that the light switch puts on more than one light for example when you turn on the lights it puts on the headlights or parking lights the dome light and the small lights in the power window and door locks at night you can see them. Tag: Why are there two hot wires on the same terminal screw?