Hello Brian, The likely clause is NFPA 70 210.8(B)(6). This clause requires GFCI protection in indoor wet locations for buildings that are not dwelling units. It is likely that the AHJ is applying their own interpretation to this clause to require a GFCI for equipment with a fixed water connection. The concern of the NEC is that if equipment has a faulty ground connection, a nearby sink other water source could provide an alternate ground return path. A person could touch both the equipment and the sink completing the loop. However, this doesn't make as much sense for equipment with a fixed water connection. You might be able to convince the AHJ that there isn't an alternate ground close by even with the water connection. If you require a copper water line, that may convince the AHJ that the equipment has a reliable alternate ground.
EMI may not be the issue causing GFCIs to trip. I've run into this problem when using electronically speed controlled motors. Leakage current for safety is measured using the human body model, which measures AC current in the 50 - 60 Hz range. The circuit of IEC 60990 Figure 4 has a low pass filter formed by R1 and C1. Equipment may have higher frequency leakage current that is blocked by the test circuit but is high enough to trip a GFCI. I once had an air conditioner with an electronically speed controlled motor. A standard meter read a leakage current of 9 mA while the IEC 60990 Figure 4 circuit read about 2 mA. The equipment was safe, since the higher frequency currents were too high of frequency to interfere with the human heart rhythms. (The IEC 60990 circuit is designed to detect only the current that is harmful to people.) However, the GFCI looks at current of any frequency. If the problem is high-frequency leakage current, additional EMI suppression may not help. One option is to consider a locking plug for your product. If you supply your product with a NEMA L6-20 for example, it won't plug into a standard outlet. The NEC has a number of exemptions for equipment plugged into a circuit with a single outlet or to industrial locking outlets. The AHJ may consider the outlet as providing a reliable ground connection if it is a purpose installed outlet not serving any other equipment. Consult with the AHJ to see if there are conditions under which the GFCI will not be required. Ted Eckert Compliance Engineer Microsoft Corporation [email protected]<mailto:[email protected]> The opinions expressed are my own and do not necessarily reflect those of my employer. From: Bob Johnson [mailto:[email protected]] Sent: Friday, April 13, 2012 8:34 PM To: [email protected] Subject: Re: GFCI for 230VAC Products You need to determine more carefully what requirements must be met. There are two different ground fault concerns in the code. Ground Fault Circuit Interrupters (GFCIs) are used for protection of personnel from electrical shock and are needed in wet areas. Ground fault protection of equipment is required for motor circuits but this protection is for the wiring and motor, not protection against electric shock. GFCIs are not necessarily required simply by the presence of plumbing. GFCIs are for protection of personnel from electric shock due to wet conditions. GFCI protection is generally required for receptacles due to the poor dependability of portable circuits and grounding. Only in some areas like pools are additional permanently installed equipments required to provide protection from shock. The NEC (NFPA 70-2012) requires GFCIs in the locations below. The code in effect is the one adopted by Tennessee which may be this or an earlier version of NFPA 70 and may have modifications. The GFCI and/or motor ground fault protection is usually part of the site installation done by the local electrician. That generally makes it a burden on the owner, not the product manufacturer unless the product codes require it to be built in. Which GFCI or motor protectors to choose would often depend on the brand of electrical panel involved. The following locations require GFCIs to some extent. There are exceptions and limitations. Sometimes 120V receptacles are required. Sometimes circuits must be protected. Bathrooms Garages Crawl spaces Unfinished Basements Kitchens Sinks Boathouses Boat Hoists Indoor wet locations Showers Garages Rooftops Outdoors Drinking Fountains Spray Washers Vending Machines Hydromassage Units Pools, Spas, Hot Tubs Fountains Marinas Bodies of Water Electric Signs Electrified parking spaces Elevators and lifts Space Heating Cables Construction Sites - Health Care Facilities Mobile Homes Recreational Vehicles Pipeline Heating Aircraft Hangers Bob Johnson ITE Safety<www.itesafety.com> On 04/13/2012 10:22 AM, Kunde, Brian wrote: Our company makes a 230VAC product (laboratory/light industrial) that has a water connection. We received word from a customer in Tennessee, USA, who says the NEC and/or the Tennessee Electric Code requires a GFCI be used with this product. We are not experts in the NEC so can anyone confirm this to be true? We did not know GFCI were required for non-consumer products. Our product uses a Frequency Drive to speed control a 2hp motor. EMI from the drive causes false trips in the GFCI. On a similar 115VAC product we found GFCI based on the 2006 requirements worked just fine as was immune to the EMI caused by a Frequency Drive, but we cannot find such a reference on 230VAC GFCI. Can anyone suggest a 230VAC 2 pole GFCI that is immune to EMI from Frequency Drives? Does the NEC allow for an alternative for a GFCI such as adding a secondary earthed ground bonding conductor or wiring the power cord direct? Thank you all for your help. The Other Brian ________________________________ LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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