Imaging Equipment - Equipment Grounding Conductors

[Shujinko]

Why do imaging equipment manufacturers for MRI's, CT's, X-Rays often require for the equipment grounding conductor to be the same size as the phase conductors for the electrical feeder to their equipment? Why isn't sizing the EGC according to NEC Table 250.122 suffice? I need to explain this to my client and I want to make sure I give them the correct information.

 

[iwire]

Why do imaging equipment manufacturers for MRI's, CT's, X-Rays often require for the equipment grounding conductor to be the same size as the phase conductors for the electrical feeder to their equipment?

I think the only way to find the answer to that is to contact the manufacturer.

 

[qcroanoke]

Why do imaging equipment manufacturers for MRI's, CT's, X-Rays often require for the equipment grounding conductor to be the same size as the phase conductors for the electrical feeder to their equipment? Why isn't sizing the EGC according to NEC Table 250.122 suffice? I need to explain this to my client and I want to make sure I give them the correct information.

Some UPS mfgrs. require that.
I suspect it's because they can.......

 

[mgookin]

This is pretty off the wall but is there a periodic calibration certification where it would matter if the resistance is the same in all conductors?

 

[Shujinko]

This is pretty off the wall but is there a periodic calibration certification where it would matter if the resistance is the same in all conductors?

This is a great question, I will let you know. I am trying to get in touch with the specific manufacturer now.

 

[Shujinko]

I talked to the imaging equipment manufacturer and they said that sizing the EGC the same size as the phase conductors is ideal for them to ensure image quality. However, they also said the EGC can be sized per NEC Table 250.122 if no previous grounding problems have been recorded in the facility where the installation of the imaging equipment is taking place.

 

[iwire]

The installation is worth millions give them the full size EGC.