Greetings all: I guess I should jump into the fray, since I am an inverter manufacturer's regulatory engineer.
1. For CE marking purposes inverters should comply with EN50091-1-1 (the harmonized UPS safety standard, which borrows heavily from EN60950 but only up to A2) and with EN50091-2 (the harmonized UPS EMC standard). While this may not be obvious, it makes sense to me (and a couple of CB's that I checked with) since UPS's all contain inverters. One recently thrown-in wrench is the safety standard EN50178 (Electronic Equipment for Use in Power Installations), which is applicable to "electronic equipment with control action on systems and processes such as generation, distribution, conversion and control of electrical energy". I think the "control action" part of that eliminates inverters, but I've heard other opinions. 2. For most applications, the North American standards are CSA107.1 and UL458, although there is also an "Outline of Investigation" UL1741for power conditioning units intended for use in residential solar photovoltaic installations (basically an inverter with some fancy features, powered by solar cells, and (maybe) selling power back to the utility). 3. Yes there are high input currents, with risks of fire and energy hazards. There are also high internal and output voltages which add shock hazard to the list. 4. Yes the LVD is limited to products utilizing 50V or more, but it is easy to conclude that creating 120Vac or 230Vac and providing it to the outside world falls within the intended scope of the LVD. You can also convince yourself otherwise. 5. The output circuit is NOT necessarily considered a primary circuit. My opinion for a stand-alone inverter is that the output is a hazardous voltage secondary circuit created from an ELV input circuit (usually a battery), so there's actually no primary in the whole system! Note that "primary" is a term that carries with it implications of large transients and large available fault currents, neither of which are true of the output of most inverters. EN50091-1-1 verifies this interpretation in that it allows the use of clearances for transient-free secondary circuits (I'm over-simplifying - catch me off-line if you want more details). 6. Grounding of the output and bonding of the output neutral to ground are handled differently by different manufacturers and in different applications. Except for those rare cases where you pound an electrode into the ground, many inverter applications operate without a true "earth" but instead use a local ground (e.g. the frame of a car, boat, or RV). There are many parallels to generators regarding this issue. 7. Output waveforms generally fall into two classes: so-called "modified sine wave" (MSW) and true sine-wave. The MSW is actually usually a stepped square wave, and is suitable for many types of loads but unsuitable for others (steep rising edges can cause current spikes that some equipment doesn't take kindly to). There are lots of examples of CSA or UL approved MSW inverters, and the agencies will do testing to convince themselves the waveform doesn't pose a safety hazard in the intended applications. True sine wave inverters are more complex and costly (but that is dropping fast), but can power anything you can plug into the wall (within surge ratings) and usually provide better power quality than the utilities (especially in our building full of computers with SMPS front ends!). I hope this helps. Regards, Jim Eichner Statpower Technologies Corporation [email protected] http://www.statpower.com Any opinions expressed are those of my invisible friend, who really exists. Honest. > -----Original Message----- > From: [email protected] [SMTP:[email protected]] > Sent: Wednesday, March 24, 1999 4:24 PM > To: [email protected]; [email protected] > Subject: Re: dc-ac converter > > Hi Doug, > > First, I have to ask a couple of questions. You mentioned that this > product > will be CE compliant. If so and if this accessory is aimed at the EU, > why then > would it have North American NEMA 110V outlets? Or, does this product > when CE > marked have outlets acceptable for CE marking? Is it intended to sell > these > 110V output products (clearly not CE) into Europe to connect to this > accessory? > > I'm not sure as to the US & EU safety standard that would apply to > this type of > product, however, the output should be considered a primary circuit > and, as > such, should meet the requirements for primary circuits. At 300W > output and > assuming an efficiency of about 80%, you should be seeing an input > current of > little more than 30 Amps. With such an input current you should be at > least > concerned about heating and fault conditions. > > Anyway, these are my comments and I hope this helps. > > Best regards, > Ron Pickard > [email protected] > > PS - To all, clause 1.1.1 of EN60950 (scope) says applicability > exists for > "mains-powered" or "battery-powered" (quotes are mine) ITE ...... > with a RATED > VOLTAGE not exceeding 600V. Does the "RATED VOLTAGE" here imply to > the input, > output, or either? Just a curiosity question to throw out. > > > ______________________________ Reply Separator > _________________________________ > Subject: No subject given > Author: "Douglas Best" <[email protected]> at INTERNET > Date: 3/24/99 12:47 PM > > > A question to the experts: > > My company is considering using a portable DC to AC inverter as an > accessory > for one of our products, the product will be CE compliant bench top > portable > class one piece of equipment. This Inverter will be intended to be > connected to the DC terminals of a 12 Volt automotive battery and has > two > North American 110V Outlets, it has a modified sine wave output, and > is > spec'ed to provide upto 300Watts of AC power. > > After looking at available off the shelf designs I found some that > have some > CE declarations, but after looking closely at these I found no mention > of > compliance to any Safety regulation but only EMC. > > My question is this, is it because the inverter has a low voltage > input and > they do not have to comply to a standard like EN61010 or UL1950, or is > this > something the manufacturers haven't addressed because no one has ever > asked? > > ---------------------------------------------------- > Douglas Best Compliance Technician > IFR America's Inc. Design Engineering > RF Division Tel : +1 316 529 5327 > 10200 W. York St. FAX : +1 316 522 3676 > Wichita Ks, 67215 e-mail: [email protected] > ---------------------------------------------------- > > > --------- > This message is coming from the emc-pstc discussion list. > To cancel your subscription, send mail to [email protected] > with the single line: "unsubscribe emc-pstc" (without the > quotes). For help, send mail to [email protected], > [email protected], [email protected], or > [email protected] (the list administrators). > > > > > --------- > This message is coming from the emc-pstc discussion list. > To cancel your subscription, send mail to [email protected] > with the single line: "unsubscribe emc-pstc" (without the > quotes). For help, send mail to [email protected], > [email protected], [email protected], or > [email protected] (the list administrators). --------- This message is coming from the emc-pstc discussion list. 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