I finally did my 50 AMP 15-40 Nema wiring. Couple of questions on it.
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I don't have enough ground and neutral wire to reach the ground bar of the electric panel. Is it ok to join both neutral and ground together, just before the two wires enter the panel, and take one resulting wire to the panel's ground bar? If both can terminate separately on the ground of the electric panel, why is it even separated at first? I understand one is for fault prevention and one for return path, but ultimately they do connect to common ground bar at the electric panel.
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In my 15-50 power distribution gang box, there was an existing wire connected from ground pin to the metal body of the box. I also have the ground wire connected to the electric panel on the same pin. Is that fine or only the ground until electric panel is enough? or should I also separately connect the metal box to the ground surface.
Best Answer
No, you can't do that because a single fault would make it deadly. Consider what would happen if the combined neutral+ground wire came loose in your panel -- all the current that was trying to return via neutral wouldn't make it, and instead it'd be able to flow back along the ground wire, energizing the chassis of your appliance with 120V. On the other hand, if they're separate wires all the way to the panel, either one coming loose won't create a safety issue. What you can do instead is put a junction box next to your panel, as far as the current wires reach, then splice to a short length of new wire to get the needed reach.
You shouldn't put two wires on the receptacle screw unless it's meant for that, and it's probably not. A better way of doing it is to pigtail the ground to the receptacle: wire nut the box ground, the receptacle ground, and the incoming ground wire from the panel together.