Ray, The clause you are trying to comply with is 4.4.2.2, single fault condition for protective conductor. Per 4.4.2.2 the exception are "...except for PERMANENTLY CONNECTED EQUIPMENT or equipment utilizing a connector in accordance with IEC 309." The most common solution I have seen it to replace your IEC 320 attachment plug with a IEC 309 attachment plug.
Ned Devine TUV Product Service [email protected] 612 638 0246 ------------- Original Text From: [email protected], on 04/17/1997 9:05 AM: To: <[email protected]> Dear Friends, We have a large piece of lab equipment that uses 3 vacuum pumps and several power supplies. The controllers for the pumps are stand alone type, fully encased. We take these controllers and power supplies and install them inside our equipment. The problem that we have is that the controllers and some of the power supplies have their own EMI filtering. This causes the leakage current of each one to be between .5 mA and 1 mA, well within the limits. But when we install them inside of our end product, these add together with the EMI filters of the end product to create a high leakage current of 6 mA. (We are using EN 61010 clause 6.3.2.2, and these values are measured with the ground wire open.) I see 3 possibilities, but could use some feed back, as "there is wisdom in many counselors". 1. The controller manufacturer has stated that we could isolate the ground path to the Y caps in their unit. The draw back here is the modification of an approved component. 2. Change from a detachable line cord to a permanent wiring scheme, and provide another ground wire. So in the event the ground wire in the line cord breaks, there is another ground path. Although I've seen this, I can not find any reference to this construction in EN 61010. 3. Provide multiple line cords. I'm not sure this will work because of the disconnect requirements. Thank you for your thoughts on this issue. Regards, Ray Russell [email protected]
