Another generator question

I had to use my generator recently and was surprised at the results. I was hoping for some insight here into what I observed. I have a 5000 watt Generac generator that I am able to connect directly to my electrical panel via a sub panel that I had put in when the house was built. I can disconnect the outside line and connect the generator in. It is a 240 volt feed that I am using using off the generator. This worked well for the "easy" stuff like the TV and lights. Here is my question: I tried to use my microwave which is rated at
1000-1500 watts. Factoring in a "start-up" surge of 3 times that gives me 4500 watts, in theory not a problem for my generator. I tried running the microwave and it completely bogged down my generator, could not keep power up on the microwave, nor could I keep power up on a small off the shelf toaster. What I found out is that the cable that I am using from the generator to the outlet is about 25' long, then about another 25' via the panel/house wiring to the microwave. When I connected the generator to the microwave using the 120 volt connector via a 15' foot regular cable it worked like a champ. My theory is that the 50 foot total is causing such a voltage drop that the power reaching the microwave is decreased. Has anyone else experienced the same thing? or have similar experience? The cable that I am using from the 240 volt output was given to me by an electrical house, maybe the gauge is too big? Both the 240 volt and the 120 outlet supply 20 amps...thanks for any help...

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maybe the gauge is too big?

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By that, do you mean the gauge is too high a number, meaning a smaller diameter wire? I suspect the wire size should be larger in the hook-up cable.

Your profile does not say where you are from. Motors do not have as much output at higher elevations than at sea level.

however it still should have enough to run a microwave. Did you have anything else on the system at the time.

I have run a microwave at a 2000 foot elevation off a 1400 watt generator, where it would not run it at 7000 feet.

My guess is that when you are going through the panel that there is something else drawing on the system and you are not getting the full power to your appliances.

The cable from the generator to the electrical box may have the quage marked on it. If not check in the electrical box to see if you can tell the gauge. It should probably be about 8 or 10 for proper operation. Does the line from the generator to the electrical box get warm/ hot when the micro wave is on? Are there other electrical appliances that are on when you try the micro wave?
Perhaps an inspection of the in house disconnect box is in order. There may be such a thing as a connection that is not properly fastened.

Please note: I AM NOT AN ELECTRICIAN so will recommend that the inspection would be done by a qualified person.

Egon

I am not an electrician, but I do have a generator and have had to use it a number of times because of weather caused power outages.

Why don't you take the microwave out to the generator and plug it directly into the 120 volt outlet and see it it runs it? If it does, then your problem is as previously described by others on this post.

Just an idea.

Often what is happening is that in spite of the fact that you have 240 volts with two hot legs and a neutral, that the house and especially the selected wiring that you are connecting to is WIRED MOSTLY ON ONE OF THE TWO LEGS. You'll need to do some checking with an ammeter and determine if load balancing is needed. Every time I have done a residential gen set install it was necessary to load balance to get the circuits evenly balanced (loaded) leg-to-leg where the gen set could handle it. I'm re-wiring a 100-yr old Iowa farmhouse and we have a "critical loads" panel which has all of the stuff you mentioned like furnace blowers, frige, and microwave. The gen set feeds the critical loads panel ONLY. [img]/forums/images/icons/crazy.gif[/img]