Effective ground for Conduit to Box

[transman2]

Where there is a metal conduit raceway going to a junction box is it only considered effective ground if the conduit has bond jumpers from a ground bushing to the box. I'm reading 250.148 and my conductors are not spliced or terminated in the box.

 

[Dennis Alwon]

The conduit is an effective means however if the equipment grounding conductor is spliced then the box must be bonded also. Is that what you were asking?

 

[iwire]

Where there is a metal conduit raceway going to a junction box is it only considered effective ground if the conduit has bond jumpers from a ground bushing to the box. I'm reading 250.148 and my conductors are not spliced or terminated in the box.

Depending on the voltage, KOs and listing you may not need anything at all.

 

[transman2]

The conduit is an effective means however if the equipment grounding conductor is spliced then the box must be bonded also. Is that what you were asking?

Dennis,

So if there's a splice of any kind then the box must be bonded.

If there are multiple conduits and lets say 1 has no EGC, does that mean the conduit has to be bonded to the box by a grounding bushing?

 

[augie47]

The first step is to back to Iwire's post ( #3).
To determine if the box is effectively grounded by a conduit system listed in 250.118, you have to consider the voltage (over 250vtg ?) , if there are any concentric knockouts involved and if the box is listed as suitable for grounding with such knockouts.
Second step is to look at 250.148 which basically tells you if there are any splices or terminations in the box and grounding conductors involved must be bonded to the box.