Can I ground junction box directly to panel?

Question

I have a metal junction box but I'm currently using as a pass-thru for the wires running through it. It's the incoming box from outdoor underground conduit burial. My ground wire is just barely long enough so I'm afraid to splice it and reconnect it using a wire nut so the box can be grounded. Is there a way to splice it securely so I don't have to worry about the splice coming loose? If not, can I just run a 4th wire from the jbox to the panel and consider it grounded safely?

I do have the hot wire in the box with a wirenut right now because it was a couple inches short so I had to cut it and extend it.

Answer 1

If that wire nut comes loose it sounds like you could end up with not only a HOT BOX but perhaps HOT CONDUIT also.

I trust you can imagine the possibilities of misfortune that can result from that.

It is well worth whatever it takes to prevent that from happening. What you want is to have a breaker trip instead.

Splicing ground wire is safe when done correctly. But if your length simply can't reach or if the splice can't be made to fit inside the conduit, then the only option would be a new length of ground wire.

Call it cheap insurance.

Answer 2

Here are some pertinent articles of the National Electrical Code:

314.4 Metal Boxes. Metal boxes shall be grounded and bonded in accordance with Parts I, IV, V, VI, VII, and X of Arti‐ cle 250 as applicable, except as permitted in 250.112(I).

...

250.148 Continuity and Attachment of Equipment Grounding Conductors to Boxes.

If circuit conductors are spliced within a box or terminated on equipment within or supported by a box, all equipment grounding conductor(s) associated with any of those circuit conductors shall be connected within the box or to the box with devices suitable for the use in accordance with 250.8 and 250.148(A) through (E).

...

If not, can I just run a 4th wire from the jbox to the panel and consider it grounded safely?

You should run another equipment grounding conductor from the panel to the box. Then splice the equipment ground and bond it to the box with a #10/32 green grounding screw in the tapped hole in the box.

Good luck!