Doug,
Altho I am not completely familiar with 60601-1 since I haven't
worked with it for a number of years, I will comment on leakage current
requirements for earthed equipment in general.
By and large it is recognized that earth/ground is unreliable for
cord connected equipment around the world. (I know that US medical
facilities work harder than most to provide a proper earth, but that doesn't
negate the comment). For this reason safety standards specify a leakage
current (Touch Current) limit for the normal, earthed case - 0.1mA as you
have mentioned for your case. So, for this product - when the earth is not
present - the patient will not get more than the 0.1mA allowed.
I would be surprised if there were an exception in 60601 to allow
anything higher than this.
You could, of course, provide for a permanent, hard wired electrical
connection for the equipment which will provide a permanent, secure
earth/ground. Conversely you could provide an isolating transformer for the
product which would isolate the product from ground so that there would be
no leakage current to ground other than the leakage current from the
transformer (a good double insulated one). I'm sure that neither of these
seems attractive. Surely you can get a proper motor with low leakage
current for this application,
:>) br, Pete
Peter E Perkins, PE
Principal Product Safety Engineer
PO Box 23427
Tigard, ORe 97281-3427
503/452-1201 fone/fax
[email protected]
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