Portable generator/ hookup questions.

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Old 03-02-17, 09:44 PM
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Portable generator/ hookup questions.

I bought a WEN 3000 Watt Portable Generator.

I also installed a Reliance 30 Amp NEMA 3R Power Inlet Box via an interlock kit. I wired it as:
  • Red - X - Phase 1
  • Black - Y - Phase 2
  • White - W - Neutral bar
  • Green - G - Grounding bar

When I hooked everything up, my microwave was only pulling 100 watts (rated for 1,800w).

I called customer service and the representative advised me to disconnect safety ground inside the inlet box.
I performed this change and the microwave started pulling 1,300 watts.

Is this the correct setup (disconnecting safety ground)?
Why support an l14-30 receptacle if only 3 prongs are needed?

The generator has a safety ground terminal, but the representative advised me to leave the terminal alone.
Does the generator need to be safety grounded in any manner?

The generator includes two 120v 5-20R receptacles, each rated for 25A.
However, the rated amperage for any single hot lead of the l14-30 receptacle is 12.5A

So, the microwave (again, rated for 1,800w) can only work if I use an extension cord and plug it directly into one of the 120v 5-20R receptacles?
I won't be able to use my microwave via the inlet box because the max is only 12.5A?
Is there any fundamental reason why either l14-30 lead can't provide 15A (which is still 10A under the max the generator can provide)?

This is incredibly frustrating because I assumed a 3,000w generator would be more than enough to run a 1,800w microwave. I thought I understood how all this worked, but I guess not.
 
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Old 03-03-17, 04:18 AM
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my microwave was only pulling 100 watts
How did you measure this?

Do as the manufacturer suggests since they built the unit. Is the microwave the only thing you are running on this generator? No lighting, no refrigerator. All the other breakers in the panel turned off, except microwave?
 
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Old 03-03-17, 05:28 AM
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What interlock kit did you use and how is that connected?
Geo
 
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Old 03-03-17, 06:38 AM
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Something sounds wrong. The egc normally plays no part in circuit operations. It is there for safety. Disconnected you are loosing an important safety measure.
 
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Old 03-03-17, 07:50 AM
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However, the rated amperage for any single hot lead of the l14-30 receptacle is 12.5A
Where are you getting this info from? Each leg to neutral (120V) should provide you at least 25A capacity. You don't divide the 25A by 2. If the gen can provide 25A at 120V then it can proviide12.5A at 240V. Watts is Watts, so 3000W/120V = 25A, 3000W/240V = 12.5A

Edit: The neutral to ground bonding in the Gen should be removed when the Gen is hooked to the house system. The four wire connection to the inlet is correct. What size/type breaker and wire did you use to connect the power inlet to your house panel?
 

Last edited by pattenp; 03-03-17 at 08:06 AM.
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Old 03-03-17, 08:10 AM
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What interlock kit did you use and how is that connected?
I believe you are thinking of a transfer switch. Interlock kits are not connected to the wiring They are a simple metal bracket that keeps the gen breaker from being turned on without turning off the main breaker.
 
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Old 03-03-17, 08:49 AM
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If you want to understand all this, search google for and read about...

separately derived system

non-separately derived system

Generator transfer switch

Neutral switching transfer switch
 
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Old 03-03-17, 09:34 AM
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Pattenp,That's true,my bad..................
 
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Old 03-03-17, 10:35 AM
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How did you measure this?
Kill A Watt meter.

Is the microwave the only thing you are running on this generator? No lighting, no refrigerator. All the other breakers in the panel turned off, except microwave?
At the time of test, all circuit breakers were OFF except for the generator breaker and the microwave breaker.
 
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Old 03-03-17, 10:44 AM
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Where are you getting this info from?
Three places:
  1. I tested it and the microwave only pulled 1,300 watts.
  2. Customer service rep stated the max per lead is 1,500 watts.
  3. The manual's SPECIFICATIONS
    section
    states:
    Rated Voltage 240V/120 V
    Rated Amperage 12.5A/25A

    I'm taking this to mean 12.5A max for X or Y.
What size/type breaker and wire did you use to connect the power inlet to your house panel?
30a two-pole breaker with a 10/3 cable.

The four wire connection to the inlet is correct.
With or without safety ground connected?
 
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Old 03-03-17, 11:55 AM
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I'm taking this to mean 12.5A max for X or Y.
No, 12.5A is at 240V across X and Y. It's 25A on either X or Y across neutral at 120V. The 240 outlet should have internal protection to 30A so you should be able to pull the full 25A on either leg at 120V which is 3000W, using only one leg at a time. You can only pull 25A total between the 2 legs at 120V at the same time. So at 120V you can pull 25A on L1 and 0A on L2, or 0A on L1 and 25A on L2, or 10A on L1 and 15A on L2, and so on as long as the total watts don't exceed the Gens capacity. This is only when using the 240V outlet. The Gens individual 120V outlets are probably protected to a max 20A.

Edit: How can the max per lead be 1500W? This is from your manual.

NOTE: Although the overall rated wattage of the machine is 3000 Watts, it is not recommended that you attempt to draw more than 2400 Watts (20 A) from any ONE of the 120 Volt receptacles.


With or without safety ground connected?
Four wire connection is with the equipment ground connected to the house which is required when connecting Gen to house system.
 

Last edited by pattenp; 03-03-17 at 12:12 PM.
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Old 03-03-17, 02:04 PM
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Edit: How can the max per lead be 1500W? This is from your manual.

NOTE: Although the overall rated wattage of the machine is 3000 Watts, it is not recommended that you attempt to draw more than 2400 Watts (20 A) from any ONE of the 120 Volt receptacles.
The 2400 Watts (20 A) recommendation is for the 120v 5-20R receptacles...neither of which I'm using. I AM using the l14-30 receptacle.
Again, I can only pull 1,300 watts via my microwave from L1 in my breaker panel. Which doesn't seem to indicate L1 or L2 can pull all 25A at once.

Four wire connection is with the equipment ground connected to the house which is required when connecting Gen to house system.
Sorry, I'm a little confused with the terminology...
Is "equipment ground" referring to the neutral (white) wire or safety ground (green/bare) wire?
When safety ground from the l14-30 is connected to safety ground in my electric box, the generator produces little current.
It's only when I disconnect the safety ground, do I get ample current.
I'm trying to understand why this is the case. (and if it's safe to disconnect safety ground)
 
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Old 03-03-17, 02:40 PM
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Is "equipment ground" referring to the neutral (white) wire or safety ground (green/bare) wire?
Neutral though a grounded conductor is not a ground. There are two types of ground.

EGC (Equipment Grounding Conductor) that provides a low resistance path to trip a breaker if the hot (ungrounded conductor) contacts the metal shell of the equipment, device or fixture. This could be called a safety ground.

GEC (Grounding Electrode Conductor) is to a ground rod(s)* from any system metal such as enclosures. It is to equalize atmospheric charges between equipment and earth to reduce the chance of lightning damage. No GEC is used on the generator if it powers a system that already has a GEC such as your house syste.

The ground wire of a four wire system in a house is a EGC.

Neutral is the center tap on the secondary of the transformer supplying 240 volts to your house. The neutral is grounded at the transformer and the first panel (board) at your house with an over current protection device (OCPD).

Note 120v volts in your house system is a derived voltage from one leg of the 240v and neutral.

*If the water pipes are metal they are bonded to the GEC also.
 
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Old 03-03-17, 02:43 PM
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The L1 and L2 are the same phase outputs used for the two 120V outlets. Something is not right with your setup. The equipment ground is the green. The gen ground being hooked to the house ground should not cause the gen to produce less power. And it's not safe to not have the EGC connected when using the Gen to power your house. Also you never answered about unbonding the neutral in the Gen.
 

Last edited by pattenp; 03-03-17 at 03:06 PM.
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Old 03-03-17, 03:04 PM
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I'll add is if the L1 and L2 can only output 12.5A independently and not 25A then why in the world does the gen have a L14-30 outlet which is 30A? The 120/240 outlet should only be a L14-20
 
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Old 03-03-17, 06:52 PM
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Just curious,how does the microwave work plugged directly into the generator via an extension cord?why are you using a KW meter instead of a clamp on amp meter?
Geo
 
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Old 03-03-17, 09:20 PM
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Also you never answered about unbonding the neutral in the Gen.
I'm not totally sure what this means, so I guess the answer is, no.
How is this achieved?

I guess, taking a step back, is this the right setup?
  • X --> Red wire --> panel L1
  • Y --> Black wire --> Panel L2
  • W --> white wire --> Panel neutral bar (same place as other circuit neutrals/ white wires)
  • G --> green/bare wire --> Panel safety ground bar (same place as other circuit safey grounds/ bare wires)

Fundamentally, is this the correct approach?
 
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Old 03-03-17, 09:25 PM
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Just curious,how does the microwave work plugged directly into the generator via an extension cord?
I will test this tomorrow and report back.

why are you using a KW meter instead of a clamp on amp meter?
That's the only equipment I possess to test current. Is there a major difference between KW meter vs. clamp on?
 
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Old 03-03-17, 09:46 PM
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Set the Kill A Watt to amps and do the test with the generator and compare to the amps on house power.
 
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Old 03-04-17, 06:15 AM
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I was not familiar with the Kill A Watt,but after doing some research it appears it would do the same thing if set to Amps.
Geo
 
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Old 03-04-17, 06:49 AM
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I'm not totally sure what this means, so I guess the answer is, no.
How is this achieved?
A portable gen is setup with the neutral and ground connected together inside the gen. When hooking the gen to the house system it's best to remove that connection inside the gen. The neutral should only be bonded to ground in one place and that is at the point of the first main disconnect which is usually the main service panel. This should not be the cause of your problem but is a safety precaution to prevent the possibility of an alternate path for current flow.

Fundamentally, is this the correct approach?
Your wires are connected correctly by your diagram. But I suggest double checking your connections.

I see there is a power selection switch on the gen. You do have that switched to 120/240 and not just 120?
 
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Old 03-04-17, 11:04 AM
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If the generator is indeed rated at 3000 watts then the most you can get at 240 volts is 12-1/2 amps . I could not explain why the 240 volt receptacle is rated 30 amps rather than 20.

The "standard" receptacles and the wiring behind them are rated at 20 amps max thus you should not draw more than 20 amps (2500 watts) from any one of them (when the power selector switch is set to 120 volts only). With the power selector switch set to 240 then each "regular" receptacle normally give you no more than 12-1/2 amps (1500 watts) whether or not the other is in use.
 
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Old 03-04-17, 11:46 AM
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With the power selector switch set to 240 then each "regular" receptacle normally give you no more than 12-1/2 amps (1500 watts) whether or not the other is in use.
All I can say that is different than any Gen I've used. If the specs say it can produce 25A at 120V then it should be able to supply 25A at 120V off one leg of the 120/240V 30A outlet with the selector set to 120/240. I can see this is a dead horse and there's no sense in beating it.
 
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Old 03-05-17, 09:08 AM
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deleted post. Misread previous post.
 
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Old 03-05-17, 07:43 PM
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Just curious,how does the microwave work plugged directly into the generator via an extension cord?
Using an extension cord to connect the microwave to the generator's 120v 5-20R receptacle, the microwave pulled ~1,650w.
Using street power (no extension cord), the microwave pulled ~1,750w.
Is the ~100w difference a cause for concern? Perhaps the extension cord?

As it relates to the safety ground issue, I believe the generator only providing 100w was my fault. Initially, upon opening the inlet box, I noticed the neutral wire was lose; possibly detached. This probably caused the low power output. Of course, this doesn't really explain why the customer service rep recommended I detach safety ground as a solution.
Today, I re-connected neutral and safety ground and the generator was supplying ~1,480w to the microwave (via l14-30).

On a separate note, I called customer support and spoke with an "engineer" who claimed each leg of the 240 receptacle should carry 25a, independently. So, we'll see where that leads me...this is in direct conflict to what the customer support rep told me.
I did get different readings today. Leg 1 produced ~1,400w and Leg 2 produced ~1,480w.....a ~80w difference.
 
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Old 03-05-17, 08:01 PM
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Is the ~100w difference a cause for concern? Perhaps the extension cord?
That is less than one amp difference. That is not significant. The amps used will very over time depending on settings and if the magnetron is on.
this doesn't really explain why the customer service rep recommended I detach safety ground as a solution.
They aren't usually experts and are just reading from a script they may not understand.
 
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Old 03-05-17, 08:10 PM
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So the engineer says 25A on each leg of the 14-30 outlet. Gee where have I heard that before?
 
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Old 03-06-17, 06:15 AM
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Bottom line,is the microwave working?I hope you are testing it with a bowl of water or something it.
Geo
 
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Old 03-06-17, 08:18 AM
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Bottom line,is the microwave working?
It is, but I can hear it lagging when not running on street power.
But it's also irritating that I bought this model for the rated wattage and I'm only NOW discovering that I'm effectively getting half that amount.
The plan was to cycle critical appliances, not power everything in the house.

I hope you are testing it with a bowl of water or something it.
I am.
 
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Old 03-06-17, 09:23 AM
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Can you return it? I believe when getting a portable Gen you should get one double the capacity of what power you plan to use at one time. Sounds like you should have gotten a 5000W - 6000W Gen.
 
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Old 03-06-17, 01:39 PM
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One other thought and I had it happen with a smaller gen. Was that the generator was not supplying a good 60 Hz. a friend bot it to power is oil fired boiler in case of emergency,and the relay in the controller chattered so bad it wouldn't maintain even though it was putting out 24VAC.
Geo
 
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Old 03-07-17, 07:20 PM
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So the microwave oven was lagging on generator power?

I suspect the microwave really wanted more amperes (more watts) than the generator was willing to give it and the next manifestation of that shortcoming is a voltage drop (measurable right at the generator's receptacle) even though the Romex cables in the wall were plenty fat enough.

What was the hot to neutral voltage when the microwave was running and pulling 1480 watts from the generator?
 

Last edited by AllanJ; 03-07-17 at 07:36 PM.
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