Equipment bonding jumper vs egc

[K2X]

I'm having a little trouble understanding this. It says the equipment bonding jumper connects two or more parts of the equipment grounding conductor.

In the textbook it shows a disco and a motor connected with a six ft piece of fmc and a ebj run on the outside of the fmc from the disco to the peckerhead. So would I still run an egc with the conductors in the fmc?

Thanks for all the help!!

 

[raider1]

If you run an EGC within the FMC then an equipment bonding jumper on the outside of the FMC would not be necessary.

Chris

 

[jumper]

I'm having a little trouble understanding this. It says the equipment bonding jumper connects two or more parts of the equipment grounding conductor.

In the textbook it shows a disco and a motor connected with a six ft piece of fmc and a ebj run on the outside of the fmc from the disco to the peckerhead. So would I still run an egc with the conductors in the fmc?

Thanks for all the help!!

I never understood that example. Why not just put the EGC in the conduit?:-?

 

[iwire]

I never understood that example. Why not just put the EGC in the conduit?:-?

If you do not want to run a wire EGC all the way back to the source but you have FMC at the end you might have to put the jumper on the outside.

 

[jumper]

If you do not want to run a wire EGC all the way back to the source but you have FMC at the end you might have to put the jumper on the outside.

That makes sense, the problem is that the example shows a EBJ going back to the source. The commentary talks about EBJs and expansion joints, and then shows a stationary motor connected to a panel with FMC with the EGC/EBJ on the outside.

FMC is okay as an EGC in lengths of 6' or less, and EBJs are limited to 6', so the example is confusing.

What am I missing?

 

[erickench]

NEC 250.118(5) gives all the conditions for a 6 ft FMC to be used as an EGC. However, even though the length does not exceed 6 ft it may still not comply with the other conditions so you would have to use an EBJ in accordance with 250.102(E).

Example: If the OCPD is greater than 20 A but the FMC is no more than 6 ft then you would have to use an EBJ.

 

[cripple]

Equipment bonding jumper vs egc

Section 348.60 requires where FNC is installed for flexibility is required, that an equipment grounding conductor be installed. This section permits the equipment grounding conductor to be installed inside or outside. Section 250.118(5) limits the length to six feet, the six foot limitation come from product standard UL 1. Section 250.8 requires the equipment grounding conductor to be terminated in an approved method.