Yes, I'm in the U.S. I'm not sure what comes into this office, as I'm leasing this space, = and never actually installed any of the wiring. I should go check the = breaker panel. The larger of the 2 twist-lock sockets says "L6-30" = and has 3 pins ( http://tinyurl.com/yj3xrxg ). The smaller of the 2 = twist-lock sockets does not have an Lx-xx type number, but also has 3 = pins ( http://tinyurl.com/ygwkavk ). I know from APS literature, that these ovens come as 220V = single-phase, but "can be wired" for 220V 3-phase. This is an older = model, but I still feel 99% sure that it's not 120V. No power info is = printed on the back of the oven. I did some basic testing... - Referencing this link again ( http://www.ezdiyelectricity.com/?p=3D238 = ), I get 120V between X and G, 120V between Y and G, and 209V between = X and Y. Both outlets are the same. - On the oven, the green-wire to ground resistance is effectively zero. I'm confused by your last paragraph -- why would I not be able to use = the 209V across the two terminals that supplies 209V? Are you saying = that a neutral is required? Cheers, -Neil. Quoting Sean Breheny : > Hi Neil, > >> From your description, it sounds like it is single phase. I would > check conductivity (with an ohmmeter) from the green wire to the > chassis. The green wire should be ground. If that is the case, then it > is certainly single phase. White is for neutral and black for hot > (line). > > HOWEVER, if you are in the US, I do not think that hot-neutral single > phase 220V is available. Is this oven meant for US electrical > standards? 220V outlets in houses in the US usually use two hot lines, > 180deg apart in phase, plus a ground wire. One hot wire is black and > the other red, typically. Such outlets will often have only the two > hots and ground, but there are types which have a neutral, too. > However, the voltage from each hot to neutral is 110V. > > In US industrial installations, the primary power source is usually > 480V three phase, which is then stepped down to 208V three phase. 120V > for lighting and outlets is derived by running circuits between one of > the 208V lines and a neutral which is connected to the wye center > point tap on the secondary of the 480V to 208V transformer. > > 220V devices are usually designed for residential use, but when they > must be installed in an industrial environment, they are typically > wired between TWO phases of a 208V three phase supply. If they require > a neutral, the wye point is once again typically used. This is a > little bit funky because (A) the total phase to phase voltage will be > 208 instead of 220, but that is usually within tolerances and (B) the > phase to ground voltage will not be 50% of the total but a little > higher (58%, that is 1/sqrt(3) instead of 1/(2)). > > So, it sounds to me like your oven, provided that it uses the standard > wire colors, and is designed for the US, is probably designed to use > 120V. Do you know what the total required wattage is? Isn't there an > electrical spec plate on the unit somewhere that would tell you about > how it should be wired? > > If your office receives 220V single phase service (two hot lines, each > 110V with respect to ground), similar to a US house, then I'd say your > L6-30 recepticle probably has connections to the two 110V hots and one > connection to ground. There should be no neutral on this plug. This > would NOT be able to supply your oven because the three wires coming > out, at least as indicated by color, have only one hot line and does > have a neutral. > > The Hubbell twist-lock plug could be any of several types. It should > also have an Lxx-xx number on it somewhere. That would allow us to ID > it. How many pins does it have? > > Sean > > > On Wed, Dec 9, 2009 at 4:22 PM, PICdude wrote: >> Hi all, >> >> Need some quick wiring assistance please... >> >> I recently picked up a used reflow oven (APS GF-12) and it does not >> have a plug -- just 3 bare wires (12ga white, green and black). =A0The >> prev owner said it was hardwired and thinks it was 3-phase, but IIRC >> 3-phase requires 4 wires... or not??? >> >> I have 2 options for outlets here at the office... >> (1) a Nema L6-30 ( http://www.ezdiyelectricity.com/?p=3D238 ) >> (2) Another similar outlet, but the prongs are in a smaller circle. >> It says "Hubbell twist-lock 20A 250V plug". >> >> So I ask... >> - Is this oven a single-phase oven? (APS only made these as 220V >> single-phase or 220V 3-phase). >> - Is there a standard for the colors on the plug wires? >> - Is there any way to check the oven =A0for the correct phase >> requirements (resistance tests, etc) before I damage the oven? >> - Are both of these outlets single phase? >> - Which wires should I connect to which prongs on the plug? =A0Assuming >> these plugs are available quickly. >> >> Google hasn't yet given me any definitive answer. =A0I have a few days >> left on my DOA warranty, so need to test fast, and APS won't speak to >> me unless I give them $2000 first. >> >> Much thanks, >> -Neil. >> >> >> >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist