Community Forums

windsorbill · 07-16-2022, 06:54 PM

Quote:

Originally Posted by Ray,IN

Re-read his post, he said "My microwave will power up and function as normal when running off of the generator but will not work off of shore power_."

What happens when the ATS shore power contacts are damaged? Answer; one or both hot legs do not conduct full power or none at all.

The reason I questioned it, is post #9, very last sentence says "I am on 50 amp with an ems and both ac will operate at the same time no problem"

So shore power IS coming through ATS, enough to run the air's..

twinboat · 07-16-2022, 09:09 PM

Plug a power strip in the microwave outlet if it's a single outlet.

Plug the microwave and a light into the power strip.

Turn them both on and see what happens.

FL420 · 07-17-2022, 12:40 AM

Buy a KILL A WATT. It's inexpensive and very useful.
[emoji40][emoji382][emoji382]... [emoji382][emoji40][emoji106]

Click image for larger version

Name: Screenshot_20220717-003403.jpg
Views: 28
Size: 36.7 KB
ID: 371233

Ray,IN · 07-17-2022, 01:20 AM

Quote:

Originally Posted by windsorbill

The reason I questioned it, is post #9, very last sentence says "I am on 50 amp with an ems and both ac will operate at the same time no problem"

So shore power IS coming through ATS, enough to run the air's..

Post 9 does not mention his microwave problem.

Olyteddy · 07-22-2022, 07:55 PM

Quote:

Originally Posted by FL420

Buy a KILL A WATT. It's inexpensive and very useful.
[emoji40][emoji382][emoji382]... [emoji382][emoji40][emoji106]Attachment 371233

Do they make a 20 Amp version? A microwave often draws more than 15 Amps & will overload the Kill a Watt.

FL420 · 07-22-2022, 10:23 PM

Quote:

Originally Posted by Olyteddy

Do they make a 20 Amp version? A microwave often draws more than 15 Amps & will overload the Kill a Watt.

I don't know if they do but you can ask them.
http://www.p3international.com/contact.html
My Sharp microwave input is 1600 watts and output is 850 watts. I haven't checked it with my Kill-A-Watt but I did check several 750/1500 watt ceramic heaters. At the High setting of 1500 watts the back of the Kill-A-Watt got warm enough to slightly scorch the outlets' faceplate when I left it on too long. It didn't seem to harm the instrument but it probably would have.
Good luck finding the info you need.
[emoji40][emoji382][emoji382]... [emoji382][emoji40][emoji106]

Ray,IN · 07-23-2022, 04:29 PM

Quote:

Originally Posted by Olyteddy

Do they make a 20 Amp version? A microwave often draws more than 15 Amps & will overload the Kill a Watt.

What amperage is designated on imlearning's breaker for the microwave? What is yours? I've never seen a microwave with a 20A plug, they all have a 15A.

20A plug

Olyteddy · 07-23-2022, 06:01 PM

Quote:

Originally Posted by Ray,IN

What amperage is designated on imlearning's breaker for the microwave? What is yours? I've never seen a microwave with a 20A plug, they all have a 15A.

I'm a retired appliance repair guy & I couldn't use my Kill-a-Watt for testing Microwaves because most of the over the range ones I worked on drew 16 Amps or so. I agree that they all have a NEMA 5-15P but they are fused with 20 Amp internal fuses. I tested them with a line splitter and a clamp meter.

bigb56 · 07-23-2022, 06:13 PM

Quote:

Originally Posted by Olyteddy

I'm a retired appliance repair guy & I couldn't use my Kill-a-Watt for testing Microwaves because most of the over the range ones I worked on drew 16 Amps or so. I agree that they all have a NEMA 5-15P but they are fused with 20 Amp internal fuses. I tested them with a line splitter and a clamp meter.

They are rated at less than 15 amps (usually 1,400 watts) but being a non-linear load you will see more than that when measuring the line with a true RMS meter. BTDT.

im learning · 08-02-2022, 08:47 AM

UPDATE:::: I finally got a chance to use my motorhome this weekend. We checked the outlet for the microwave using a multimeter and power is good. so I decided to try a different outlet. I plugged an extension cord in the bathroom far away from the kitchen and into the micro and everything works as it should on shore power. So i tried the outlet just above the countertop and no luck. Now that outlet is in direct line with the outlet above for the micro so I am assuming that is probably the same line. Then we check the power output from all 3 outlets and all are identical readings. So why will the micro not work if everything is reading the same? Again if on generator power everything works as it should but shore power...not happening. At this point if I want to use the micro on shore power I have run an extension cord to the bathroom. What could be wrong if all outlets are putting out identical readings?

code2e · 08-02-2022, 02:24 PM

Quote:

Originally Posted by im learning

UPDATE:::: I finally got a chance to use my motorhome this weekend. We checked the outlet for the microwave using a multimeter and power is good. so I decided to try a different outlet. I plugged an extension cord in the bathroom far away from the kitchen and into the micro and everything works as it should on shore power. So i tried the outlet just above the countertop and no luck. Now that outlet is in direct line with the outlet above for the micro so I am assuming that is probably the same line. Then we check the power output from all 3 outlets and all are identical readings. So why will the micro not work if everything is reading the same? Again if on generator power everything works as it should but shore power...not happening. At this point if I want to use the micro on shore power I have run an extension cord to the bathroom. What could be wrong if all outlets are putting out identical readings?

Meters measure voltage without placing any load on the circuit. It was suggested earlier to plug in a load, like a portable heater, to your microwave outlet. That would tell you if the outlet can provide current.

Something else you could try with your meter and the nearby outlet. Plug in your microwave normally and have your meter reading off the nearby outlet. Then try to start the microwave while watching your meter. Think you will see a voltage loss if they are on same circuit.

Think you will find a loose connection in your outlet or it's wiring to the breaker.

twinboat · 08-02-2022, 04:10 PM

I believe your microwave has its own circuit and breaker. It shouldn't be on a circuit with other outlets.

If you have 50 amp shore power, the problem must be in the transfer switch.

im learning · 08-03-2022, 09:56 AM

I admit that I am at a loss here and I am just throwing out questions so pleases do not take offense. If I have power to the microwave outlet when on generator power, how could there be a problem with a loose connection in the outlet? Both ac and everything else works as it should when going from generator to shore power so if I had a bad transfer switch, would that not also affect everything else also? There is not a separate circuit breaker just for the microwave at least not one that I have found anyplace. Again, I appreciate all of the help and suggestions

twinboat · 08-03-2022, 10:49 AM

50 amp shore power is like having 2 power cords to the RV, L1 and L 2.

Your generator also has 2 power cords to the RV, L1 and L2.

Both shore and generator power meet at the transfer switch. Both L 1 and L 2 are switched to the breaker panel if the generator is running or your on shore power.

L1 and L2 from the generator are switching properly.

It's possible that the L1 or L2 is not switching properly when you plug in to shore power. If that happens, about 1/2 of your 120 volt stuff will not work.