0-10v Dimming Switch in MRI Room

GoldDigger

Moderator
Staff member
The magnetic field will have no noticeable effect on the operation of the dimmer switch. But I would be concerned about the electromagnetic noise with frequency components well above the nominal 60 or 120 Hz. If the lighting system, including both the lamp and its dimmer ballast in the luminaire and all connected power and control wiring, are not fully shielded, there could be an interaction with the very sensitive electronics of the MRI detector(s).
 
Thank you, I will write up an RFI, but I wanted to do some research first. The only other MRI I have done, the switch was outside the room. Everything will be shielded with the exception of the switch itself in the wall with a regular cover plate. Would you be worried about the interference of switch itself if everything else is shielded?
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Thank you, I will write up an RFI, but I wanted to do some research first. The only other MRI I have done, the switch was outside the room. Everything will be shielded with the exception of the switch itself in the wall with a regular cover plate. Would you be worried about the interference of switch itself if everything else is shielded?
I really don't think this is something you need to concern yourself with, not your job. MRI rooms are designed by the manufacturer of the machine and if they indicate a dimmer on the inside wall I wouldn't question it. They know way better than any of us do.

-Hal
 

Fulthrotl

~~Please excuse the mess. Sig under construction~~
I really don't think this is something you need to concern yourself with, not your job. MRI rooms are designed by the manufacturer of the machine and if they indicate a dimmer on the inside wall I wouldn't question it. They know way better than any of us do.

-Hal
it was funny.... yesterday, i had a fluke 345 on a dimmed 0-10 circuit, and
just for grins, when i saw the power factor at 77% switched to the rudimentary
o scope built into the device. whew. a sine wave that looked like broken glass, arranged.

yep. real clean power there, on a 277 volt circuit. no noise... yep.... :cool:

but, you are correct. not the responsibility of anyone but the designer.
mri stuff has pretty robust shielding just to work, and not be a hazard.
i'm suspecting a little rf noise in the lights won't get thru that.
 
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