Generator power

[gsmallwood]

I have a 2003 280 Sundancer with a 5000k Kohler gen. This weekend it was cold out and we were out at the boat parade. I had the heat on in the cabin plus we were running the microwave along with Christmas lights. It tripped the power breaker on the gen. Later I had the cabin heat on and was running a small 1500 watt heater in the cockpit and it tripped again. Shouldn't the gen be able to pull more than just one thing at a time? Do they lose power after a while. Gen has 1000 hrs and runs great.

 

[sbw1]

Microwaves use lots of power. That plus an electric heater and the reverse cycle ac/heat and you will trip the breaker on a 5kw Ginny. Best load on the genny is 75 percent of rated output. Much beyond that you will experience black smoke out the exhaust followed by a shut down.

 

[JimT]

The breaker on the genny is probably 30amp. The 1500 watt heater will draw about half that. Add the microwave, the reverse cycle heat, lights, etc. its no surprise the breaker was tripping.

 

[Alex F]

I don't remember how 280s are setup with genny, but shouldn't you have an amp meter to watch the load?

To simplify, look at each component (A/C heat, Microwave, HWH, etc...) as roughly 10amp load. I don't know if you had it on, but HWH is usually overlooked having the breaker on and no load (water is hot). Then, when you use the water and the HWH kicks in, as the hot water is being used. If you didn't account for it, there goes the tripped breaker.

It all comes down to one thing only, watch your load and don't exceed rating on the main generator breaker.

 

[JVM225]

I agree with the others who responded that you were asking a lot of the genny. Those portable heaters draw a lot and so do microwaves, add the boats reverse cycle heat/ac and I’d be surprised if you didn’t trip the breaker.
That load would likely trip the breaker if you were hooked up to shorepower at the dock too if you were running a single 30 amp line.

 

[aerobat77]

yes , at 115 volts 30amps result in no more than 3.5 kw of electrical power. amp x volt .

 

[sbw1]

It is hard to maintain a load of 75 percent because things like water heaters shut down when done heating water, and the food gets cooked in the microwave, etc., but a properly loaded genny is a happy genny. Plugs last longer when working vs. loafing. In cooler weather we sometimes keep a ceramic heater running on the floor of the helm just to keep some sort of a load on the genny and to help keep the plugs clean. Even doing that plus the reverse cycle and battery charger running is no challenge for a 5Kw unit. So the output of your genny is about right for your boat but you do have to do some load shedding if you try to do too much at once. When we are on the hook and making breakfast in the morning with heat going, microwave operating, etc., I turn off the water heater. Should that kick on while the other stuff is running, we go over the limit and I have to go into the bilge and reset the breaker. I would rather not have to do that.

 

[gsmallwood]

I just had the cabin heat on and either the microwave or the portable heater. Never had them all on together. It just tripped breaker when I turned on either one of the appliances with the cabin heat. I thought I should be able to run the cabin heat and microwave at the same time.

 

[sbw1]

Calculate your load and you will know for sure.

 

[bbwhitejr]

Calculate your load and you will know for sure.

Figuring out your load will tell the story. However, I had a 5KW Koehler 5ECD on our ‘06 260DA. We ran the HVAC, HWH, microwave, coffee pot, and anything else and never had it trip. Something doesn’t sound right.

Bennett

 

[sbw1]

Figuring out your load will tell the story. However, I had a 5KW Koehler 5ECD on our ‘06 260DA. We ran the HVAC, HWH, microwave, coffee pot, and anything else and never had it trip. Something doesn’t sound right.

Bennett

HVAC, HWH, and microwaves cycle. Compressors, heating elements and magnatrons do not run all the time. You only draw peak loads when they start and then continue to run. Coffee pot heating elements are on all the time while brewing and warming coffee. Not true of the others. So you could have them on and not trip the breaker. But the amps call the tune.

 

[wyrman]

Plus, properly functioning breakers are typically designed to trip at 80% capacity. 30A x .8 = 24 realized capacity.

In my 30 years of being an electrician, I've never heard they're designed to trip at 80% of rated ampacity. Here's a c/p.
Circuit breakers are designed to carry 100% of their rated current while the NEC dictates an 80% application. Why the difference?

One of the most often asked questions is, "How do I size a circuit breaker?" A commonly misunderstood fact about circuit breakers (CBs) is related to the percentage of loading permitted by the NEC and the CB design, and why the two may be different. Let's investigate both aspects.

CB Design
A CB is designed and evaluated to carry 100% of its rated current for an indefinite period of time under standard test conditions. These conditions, per UL 489, Underwriters Laboratories Standard for Safety for Molded-Case Circuit Breakers and Circuit Breaker Enclosures, include mounting the CB in free air (i.e.: with no enclosure) where the ambient temperature is held at 40 [degrees] C (approximately 104 [degrees] F). Under these conditions, molded-case CBs are required not to trip at rated current.

However, a CB most frequently is applied in equipment at 80% of its rated current under

NEC Sec. 384-16(c). If you understand why this requirement is in place, you'll be able to apply CBs correctly.

 

[northern]

Inrush current can high. We have a watermaker that has 15AMP breaker. We have a 2500watt inverter. The watermaker will not start with the inverter. The generator we have is two sided with 33 AMPs per side. When we start the watermaker we need to have no big power draw on it. IE stove. After the watermaker is on we can turn the stove on.

 

[potis]

You guys are correct. I was having a brain malfunction. I was thinking of design factors where engineers often design systems to only load CBs to 80%. My aploogies for the bad info. Thank you for correcting me. I have deleted my previous inaccurate post.

 

[Gucci]

I guess this might be my problem too, I had the water heater and cabin heater on at the same time, I smelled smoke and power went out. Where is the trip breaker under the bilge? And since I can’t lift the bilge where is the bilge opener by hand?