Microwave and amps used December 21, 2014, 03:37:14 pm Yahoo Message Number: 149982First, let me say that I am not good with the technical side of how electricity works. I have read several things on RV electricity and for some reason the technical information just never clicks for me. But I know that I should only run one high amperage drawing appliance at a time (meaning air conditioner, microwave, electric heater or anything that produces heat or cold air) due to the limit of 30 amps. I have a Progressive Industries electrical management system (EMS) and I always make sure when I hook up that I have good power. I have been full timing for 5.5 years in my 2008 Lazy Daze mid-bath and thought I had a good handle on how to use the limited power we have. Recently I smelled something like burning plastic when running one of the above appliances. But it didn't happen all the time, just occasionally. I had the Lazy Daze at the shop last week and after some work, they found a slightly burned wire that lead to the transfer switch (I think its the switch that deals with the generator and 120 volt coming in from the external electrical box). They ended up replacing the transfer switch and a circuit breaker. They said I had probably run too much at once. I told them I was very careful about that, but I can't say it never happened. Anyway, since then I have been watching my amps very carefully on the EMS in the last few days and noticed something that I thought was strange. When I run the microwave the amps increases by 16 to 21 amps on the EMS (and I checked this several times just in case something else came on at the same time). Most things I read say the draw for a microwave should be 12 - 15. I plugged in my Kill-a-Watt and it shows it uses between 14 and 15 amps. So question 1, does anyone know why there is a difference between the EMS and the Kill-a-Watt? Question 2, how many amps does your microwave draw and is this from a EMS or a Kill-a-Watt? My microwave is the original that came from the factory. I was wondering if something is wrong with my microwave or perhaps the wires to the outlet. I plugged a blow dryer into the outlet that the microwave is plugged into (unplugged the microwave) and the EMS and Kill-a-Watt are about the same amps. (13 amps from EMS and 13.3 from Kill-a-Watt).Any thoughts or suggestions on this?Thanks for your help with this. Pam
Re: Microwave and amps used Reply #1 – December 22, 2014, 08:57:53 am Yahoo Message Number: 149993The microwave should never draw 15 amps, or higher (doesn't it run from a dedicated 15 amp breaker?) If it does, there is very possibly a problem with it. You should confirm the current consumed by it alone. Make sure something else did not pop on at the same time like the power converter, leading you to a false conclusion. Shut all the breakers off, except for the Microwave and check your readings again.Small differences in the readings between instruments should be expected, in the range of 5-10% max or so. Your comparing the readings from EMS and the Kill-a-watt is very prudent.You have a better understanding of things electrical than you give yourself credit for. -Dave '06 MB, Indianapolis
Re: Microwave and amps used Reply #2 – December 22, 2014, 11:08:34 am Yahoo Message Number: 149995The Microwave is on a 20 amp breaker not a 15 amp breaker. On all LD MH except the 30 foot the MW is on a dedicated breaker. On the 30 foot the coffee maker is also on the same breaker. This is taken from the 2005 Manual that came with the MH. I do not know if a change was made before or after this. As for the Dometic MW that LD installed in my 2005 MH (MW has a lable of Oct 2004) It is rated at 13 amp. While we are on the 110 power to the LD MH LET ME ASK THIS QUESTION.How many owners know the proper way to shut the gen set DOWN??? The microwave should never draw 15 amps, or higher (doesn't it run from a dedicated 15 amp breaker?) If it does, there is very possibly a problem with it. You should confirm the current consumed by it alone. Make sure something else did not pop on at the same time like the power converter, leading you to a false conclusion. Shut all the breakers off, except for the Microwave and check your readings again.Small differences in the readings between instruments should be expected, in the range of 5-10% max or so. Your comparing the readings from EMS and the Kill-a-watt is very prudent.You have a better understanding of things electrical than you give yourself credit for. -Dave '06 MB, Indianapolis
Re: Microwave and amps used Reply #3 – December 22, 2014, 01:52:09 pm Yahoo Message Number: 150006Even inadvertently overloading a circuit should never ever cause a burning smell or melting wires. Protecting wiring from overload is one of the functions of fuses and circuit breakers. If they are sized and installed properly, then they will trip or blow first, before wiring overheats and causes a potential fire hazard.In our LDs, a burning smell or overheated wiring is commonly caused by loose electrical connections rather than a too high current condition. This occurs even though the circuit current is well below the rating of the circuit breaker or fuse (so the safety device doesn't serve to protect against this. A loose connection causes high resistance at that point. The additional resistance causes a voltage drop across the connection and this dissipates electrical power as heat.The underlying cause of this problem is the soft copper stranded wire and the type of connectors used. Copper, when clamped in a screw connector, tends to "flow" as the copper displaces. Couple this with the movement and vibration of the vehicle and you can get loose connections over time.The quick fix is to tighten the connections and do so on a regular basis. IMO, a better fix is to install crimp on ferrules on the stranded wire ends, then the ferrule goes into the screw clamp connector.The safe way to do all this is to remove AC power first, unplug and stop the generator. Also disconnect the negative terminal on the battery bank or throw the disconnect switch. If you have solar, either remove the fuse or cover the panels with towels, trash bags etc.Now you can check wire terminals with no risk for inadvertently shorting out things with a wayward screwdriver.Ferrules f 0.34 to 50 mm ² insulated, non-insulated Twin individually or range
Re: Microwave and amps used Reply #4 – December 22, 2014, 05:09:22 pm Yahoo Message Number: 150014If this in regard to a burning smell with the use of the MW. The MW electrical wiring should not be stranded that is done by LD. The 110 volt side of power from the breaker box should all be romex not stranded. Romex for 15 amp breaker will be not less than 14 gauge and for 20 amp not less than 12 gauge.GeorgeRetired plumber.
Re: Microwave and amps used Reply #5 – December 26, 2014, 08:59:53 pm Yahoo Message Number: 150075"The microwave should never draw 15 amps, or higher (doesn't it run from a dedicated 15 amp breaker?)"My 2003 midbath's Dometic microwave oven (made by LG Electronics) is rated at 13 A, but it runs from a 20 A breaker. (Another 20 A breaker is dedicated to the air conditioner.)Andy BairdTravels with Andy
Re: Microwave and amps used Reply #6 – December 27, 2014, 10:55:01 am Yahoo Message Number: 150085"The microwave should never draw 15 amps, or higher (doesn't it run from a dedicated 15 amp breaker?)"My 2003 midbath's Dometic microwave oven (made by LG Electronics) is rated at 13 A, but it runs from a 20 A breaker. (Another 20 A breaker is dedicated to the air conditioner.)Andy Baird Our MW is rated at 13 amp by the label at the door. The circute is a 20 amp breaker. Not wort testing. In most cases it is dedicated. In the 31 ' MH it is shaired with the Coffee maker.http://www.andybaird.com/travels
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Topic: Microwave and amps used (Read 19 times)
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