Xray Disconnect

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steve66

Senior Member
517.72(A) refers to a required disconnecting means for a medical xray installation. The Xray company typically wants this disconnect installed right by the xray generator so their service tech has convinent access to the disconnect. Then they usually require an EPO switch at the operators station (behind the lead screen wall) for use by the operator.

517.72(B) says:

Code:
Location.  The disconnecting means shall be operable
 from a location readily accessible from the Xray control.
My question is what does "Xray control" mean? Do you take that to mean the operators location behind the lead screen wall? Our electrical inspector interpert's it that way, and I always have to show a second disconnect at the operators station.

Or could "Xray control" be similar to a "motor control" location? If this were the case, I would consider the xray generator to be the "control" location. And the single disconnect that the Xray vendor's drawings always show would suffice.

Steve
 

Volta

Senior Member
Location
Columbus, Ohio
...My question is what does "Xray control" mean? Do you take that to mean the operators location behind the lead screen wall? Our electrical inspector interpert's it that way, and I always have to show a second disconnect at the operators station.

Or could "Xray control" be similar to a "motor control" location? If this were the case, I would consider the xray generator to be the "control" location. And the single disconnect that the Xray vendor's drawings always show would suffice.

Steve
I would consider it required to be readily accessible from the location in which the operator controlling the equipment is stationed. If the X-ray apparatus fails to end its cycle properly, the X-ray tech can quickly stop the excessive dosage of rays. There are only about a half-dozen uses of the phrase 'readily accessible from' in the book, and they all seem to have to do with an emergency shutdown, rather than a simple maintenance disconnect, IMO.
 

steve66

Senior Member
I would consider it required to be readily accessible from the location in which the operator controlling the equipment is stationed. If the X-ray apparatus fails to end its cycle properly, the X-ray tech can quickly stop the excessive dosage of rays. There are only about a half-dozen uses of the phrase 'readily accessible from' in the book, and they all seem to have to do with an emergency shutdown, rather than a simple maintenance disconnect, IMO.
Thanks for the response, but 240.24 requires almost all overcurrent devices to be readily accessible. So I'm not sure I buy the argument that something "readily accessible" is intended to be available for emergency use. In fact, according to the definition of readily accessible, something readilly accessible could even be behind a locked door.

Our local electrical inspector has always required us to add a second disconnect at the operators control location based on this reference. (Even though there is always a ESTOP shunt trip button at this location.)

After reading your response, and reading the definition of readilly accessible, I read this section again. It doesn't say what I thought it said at all. There's Charlie's rule again.

517.72(B) says the disconnect must be operable from a location readily accessible from the Xray control.

It does not say the disconnect has to be at control location. Only that it has readily accessible from the control location. From the definition of readiy accessible, that could mean down the hall and in a closet as long as the xray operator has access to the disconnect.

Does anyone agree or disagree??

Steve
 

anbm

Senior Member
I have seen xray disconnect was installed in a equipment closet nearby but not actual in the Xray room neither control room. As long as you have EPO at control station and inside xray room so operator can activate easily in emergency case, I think you are okay.
 

benaround

Senior Member
Location
Arizona
Steve,

I agree with your 'new' opinion, I also find it a bit strange that the IE would want untrained

people opening an electrical circuit through a disconnect, and there is a 'user frendly' EPO

provided ?

The code is funny like that, you can read something for years and think it means 'xxxx' and

then one day BOOM, oh, that's what that means. Good Luck with EI.
 
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