Comparison Home Stand By Generators

[bigdeano]

can anyone suggest a meter, digital preferably, showing the amps consumption?
Putting a clamp ammeter on the feed line I suppose would work, but how about
a nice wall gauge or even a small one that would fit where a breaker is...
I'd love to see what the system surge and constant draw numbers are to best shed load if need be.

I put current meters on my 10kw diesel generator. I bought 2 1000:1 current transformers and mounted them in a 6 x 6 junction box next to the generator receptacle in the garage. I mounted 2 50ma AC meters in the kitchen and connected them to the transformers with buried sprinkler wire. I bought the transformers and analog meters on fleabay. They came directly from China. I tested the meters with my DMM and they're very accurate. The whole setup didn't cost much. It's nice to know how much load is on each leg of the generator.

 

[s219]

I put current meters on my 10kw diesel generator. I bought 2 1000:1 current transformers and mounted them in a 6 x 6 junction box next to the generator receptacle in the garage. I mounted 2 50ma AC meters in the kitchen and connected them to the transformers with buried sprinkler wire. I bought the transformers and analog meters on fleabay. They came directly from China. I tested the meters with my DMM and they're very accurate. The whole setup didn't cost much. It's nice to know how much load is on each leg of the generator.

Have any example links for the transformers and meters? This sounds like something that would be great to do for my 21kW diesel.

 

[bigdeano]

Try this link. There's lots of info by googling current transformer.

Current Transformer Basics and Current Transformer Theory

 

[yan man]

I have researched this for my home I found the Consumer Reports very helpful, it ran both Wheeled units and stationary and gave results for Gas, Diesel, and Propane. Go to you area library it was published in the Fall of 2014. I have decided to go with Propane Generac 8k, which come with a transfer switch. My big decision is weather to buy online, or from Lowe's (they offer a discount to Vet's-10%). Good Luck.

 

[s219]

Try this link. There's lots of info by googling current transformer.

Current Transformer Basics and Current Transformer Theory

I was really asking for links to buy the stuff. I did find some 100A clamp-on transformers on eBay for about $10, ship from China, which ought to do the trick. Now need to find some basic ammeter displays. Would be great to find some that can do the scaling for direct read without having to build a little controller circuit. Any suggestions?

 

[oldgeezer]

I have not seen this mentioned tho I may have missed it. If it has been, here it is again.
RE backfeeding house from a swimming pool , dryer, etc. or worse from a 120 v plug somewhere handy. Even if you throw the main or cut loose from the street power to avoid killing power linemen you still have created a probable extreme fire hazard to your home. The plug you are backfeeding is fed by small gauge wire. In some cases as small as 12 ga. or even 14 ga. The power source should start at the point of the heaviest ga. wire & work it's way down to the appropriate ga. for the appiance operating at that location. What you are doing in the case of starting the power load thru small gauge wire is creating extreme heat in your wiring. I mean extreme heat. This can burn down your home or your neighborhood. Sometime just plug a 1500 w. appliance like a hairdrier or space heater into a 14 ga. extension cord for a while then feel of the cord how hot it has gotten. The longer the cord, the hotter it will get. Too much resistance in small gauge wire. And that is just pulling 1500 w. A water heater has two 4500 w elements in it alone & clothes driers, heat & air units & ranges pull more than that. Spend a couple hundred on some sort of transfer switch. It's cheap insurance. I have a 15,000/22,500 Generac gas power on a transfer switch with a sliding plate that prevents me from have both generator & street power on line at the same time. Remember, ALWAYS feed thru the heaviest gauge wire 1st & your properly installed house wiring will serve just as it does from street power. No melting, stinking hot wiring in your walls & attic just waiting to ignite something.

 

[bigdeano]

I was really asking for links to buy the stuff. I did find some 100A clamp-on transformers on eBay for about $10, ship from China, which ought to do the trick. Now need to find some basic ammeter displays. Would be great to find some that can do the scaling for direct read without having to build a little controller circuit. Any suggestions?

They have matched sets on ebay which might be your best bet. Don't know if you want analog or digital. Don't know how far apart your transformer and meter will be. Looks like most on ebay have 5A secondary which might cause inaccuracy on a long run. You'll have to do the math. That's why I went with the ones that have 50ma secondary in my 50A application so I could use small wire. ebay is the only place I've ever looked at them, I'm far from an expert on these.

 

[jacspath]

I concur about he PTO idea. In the Catskills we often have a 2 day outage and that is a lot of time to have your PtO tied up. Propane is great, but means you can't move the gen around without a lot of re plumbing. Gas/diesel is more exp. but hey, you are not running it that many hour/yr. I assume.

But definitely get a battery start unit. My wife cannot pull start our 7.5Kw WEN unit [and have a trickle charger hooked to it so you are sure it will have a full charge when needed]. Also look for a unit with at least a 10 hour fuel tank so you don't have to get up at 2 am to refill the tank.

And, unless you spring for a whole house unit, don't forget that you will have to pull some breakers off when you put the gen on line. I put in a separate breaker panel with just the circuits that I want to energize with the gen. That way, I [or more importantly, my wife] only have one breaker to throw to switch from whole house line to selected gen power.

Also, I was not that happy to think of the gen coming on automatically when we were away from home. Not that we go away so often, but going away for a couple of weeks of vacation and knowing that the gen might be running that whole time would keep me from enjoying myself. So I have a couple of good friend neighbors give me a call if the power is out for more than a day and we all go and start each others units for a few hours a day to keep the heat [good insulation is a must in cold climes] up and the refer/freezer cold.

Think the whole system [including how you want to use it under different circumstances] through very thoroughly before you worry about which unit to pick.

 

[s219]

I have not seen this mentioned tho I may have missed it. If it has been, here it is again.
RE backfeeding house from a swimming pool , dryer, etc. or worse from a 120 v plug somewhere handy. Even if you throw the main or cut loose from the street power to avoid killing power linemen you still have created a probable extreme fire hazard to your home. The plug you are backfeeding is fed by small gauge wire. In some cases as small as 12 ga. or even 14 ga. The power source should start at the point of the heaviest ga. wire & work it's way down to the appropriate ga. for the appiance operating at that location. What you are doing in the case of starting the power load thru small gauge wire is creating extreme heat in your wiring. I mean extreme heat. This can burn down your home or your neighborhood. Sometime just plug a 1500 w. appliance like a hairdrier or space heater into a 14 ga. extension cord for a while then feel of the cord how hot it has gotten. The longer the cord, the hotter it will get. Too much resistance in small gauge wire. And that is just pulling 1500 w. A water heater has two 4500 w elements in it alone & clothes driers, heat & air units & ranges pull more than that. Spend a couple hundred on some sort of transfer switch. It's cheap insurance. I have a 15,000/22,500 Generac gas power on a transfer switch with a sliding plate that prevents me from have both generator & street power on line at the same time. Remember, ALWAYS feed thru the heaviest gauge wire 1st & your properly installed house wiring will serve just as it does from street power. No melting, stinking hot wiring in your walls & attic just waiting to ignite something.

I am all in favor of a proper transfer switch or interlock feeding directly into the panel, but if I understand what you're saying about back feeding through a branch circuit, the breaker on that circuit would trip if the amperage back fed through the circuit into the panel exceeded the wire's capacity. So in other words, if you back feed through a 40A dryer plug, the max current is going to be 40A before that breaker trips. You'll never exceed the wire's capacity.

 

[aczlan]

I am all in favor of a proper transfer switch or interlock feeding directly into the panel, but if I understand what you're saying about back feeding through a branch circuit, the breaker on that circuit would trip if the amperage back fed through the circuit into the panel exceeded the wire's capacity. So in other words, if you back feed through a 40A dryer plug, the max current is going to be 40A before that breaker trips. You'll never exceed the wire's capacity.

The key is to make sure that your wire is sized to match the breakers on both ends (in the panel and on the genset).

Aaron Z