EMI/EMF from AC unit and Farady Cage

[buddy91082]

We are working on a lab facility with sensitive electronic equipment. We hav tried to keep out all EMI/EMF emitting equipment out of the room. Unfortunately, the only space the air handling units can fit are within the ceiling of the lab space.

To mitigate EMI/EMF from the air handing units motors and other electronic equipment, we are propsoing to use the air handling unit's metal enclosure as a shield and ground it back to the main ground bar via a bare copper ground conductor.

Ha anybody have experience with a similar situation or any other suggestions?

Thanks.
b

 

[davidbeach]

I love it, design by accountants. Just get the air handler the he!! out of the space. The ceiling space above the lab is not the only space, it just may be the only space that the accountants are willing to pay for. Fire the accountants and do the engineering right.

 

[jghrist]

If the installation is accordance with NEC, the metal enclosure is already grounded to the main service ground by an equipment grounding conductor (EGC).

 

[DRWeig]

Yah, davidbeach has the answer...

The architects (not accountants, though they had some say in it) tried that with my firm in the space above the ceiling of an EEG lab in a hospital. They actually said that "...a good engineer would find a way to shield the equipment at no additional cost."

All I had to do was show the plans to one of the doctors. Suddenly, new plans materialized, in which there appeared a mechanical room far, far away for the air handler and a magical chase for the ductwork.

jghrist is right too. It won't help if the lab equipment is really sensitive.

Good on ya,

Goober Dave