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Date: Fri, 26 Oct 2012 15:53:11 -0700 To: "Don Seager"
From: Scott

Subject: Re: [Country-Coach-Owners] Running Your Gas Absorption Refrigerator on the Inverter
Don - Thanks for sharing your knowledge and experience. I fully support the NEC and understand its value as a safety measure. No issues there. Good points about upstream protection and I fully understand.
My mods deal with the inverter sub panel. Photo here: http://muniac.smugmug.com/Travel/Country-Coach-2006-430-Allure/i-kXCvqtw/0/L/Breakers-L.jpg Applying the upstream protection idea, I have 4 circuits (3 15 amps and 1 20 amp) totalling 60 amps. Upstream from that but downstream from the inverter output is a 30 amp breaker. An interesting choice for a 2800 watt inverter given the breaker won't pop before 3600 watts of power is drawn. Upstream from the inverter's AC input is another 30 amp breaker which is downstream from that leg's (line 1) 50 amp breaker. The inverter circuit uses #10 wire so the wire is protected and so is the inverter when it's in charge mode. That is when it's AC input and AC output are connected together. But when its inverting, the 30 amp breaker is too large. I gather the fallback position is relying on what's integrated into the inverter for protection circuits. Either way I don't think there are any safety issues or hazards with how it's wired and protected. There is always some fiddling room as I'm sure your know.
In my case, it would have been great (and much simpler) to just add a 5th 15 or 20 amp circuit to the inverter sub-panel to run the frig. Physically this just isn't possible since no more spare capacity (or space) exists. I also seem to remember reading in the RVIA specs something about inverters can't have more than 4 circuits attached. So that leaves one in a bit of a pickle. The last resort being to share a circuit that is well under utilized. And that's been my approach in a nutshell.
Based on your experience and expertise, how would you have solved this problem? The problem again being, providing the frig with AC power while traveling. Here you have a perfectly capable inverter that basically isn't being used. And running an 8kWatt genset seems a bit overkill for a 450 watt load. And let's assume the propane option is out. And I have no more space for another inverter either. People with residential refrigerators also face this same dilemma. And I'm wondering how the Allure folks have handled this given their breaker panel situation. If a better, safer, simpler, more practical and cost effective solution exists I'd like to get it out on the table. As of late, what I've done is the best idea I could think of. That's not to say there isn't a better idea out there I'm just waiting for it to surface. Hopefully it can come from this discussion. I like to learn new things.

At 01:44 PM 10/26/2012, you wrote:

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Scott,

A bit more on electrical protection.
The theory of protection (fuses, breaker, protective relaying) is just the opposite of what many people envision. Protective devices are installed to protect the upstream system from downstream conditions. The implementation of this rule does involve many factors according to the situation. The 15 amp entertainment circuit breaker is there because the downstream circuit is constructed with #14 copper wire rated at 15 amps continuous duty. In this case the weakest link viewpoint is applied. The individual receptacles are rated much higher than 15 amps. For whatever the cause if the load or fault current exceed the 15 amps for a designed period of time something is wrong and the circuit needs to be disconnected before the condition can spread to the rest of the upstream electrical system. The idea is that whatever is the cause is already broken and in many cases protection is too late. This very basic rule is followed all the way from the 15 amp household circuits all the way back to the generation source. Obviously it become very complicated along the way. It is sacrifice the pieces to save the whole.

I believe that you found out the hard way that the 20 amp breaker was on a different leg from the 3 - 15 amp circuits so I don't understand why you were adding 3 -15 amp and a 20 amp to get 65 amps. Of course it really doesn't really matter for even if they were the upstream 30 amp breaker would have protected the upstream system from the 65 amp overload.
Insurance companies don't refuse to pay because you did the electrical work or the plumbing. They refuse to pay because you didn't do it according to code. Whether you did it in your opinion following safe procedures or good constructions means nothing to them There are many parts of the National Electrical Code that seem ridiculous in nature from an engineering standpoint but code is code and usually there is a history behind all of it.
Installing a wood stove in the house to help avoid the high cost of fuel oil is a favorite DIY project for many. All to often at the end of the project they throw in the wood and sit back with a beer to enjoy their accomplishment. The project is however fraught with possible hidden problems that may not show up until just the right conditions exist many years later. A fire waiting to happen yet these people have paid insurance premiums for years that they might as well have thrown down the drain. All for the sake of having the fire chief check the installation before lighting up. His written approval would have foiled the Insurance company's refusal to pay up.

Don Seager

35 year veteren Power Distribution Engineer for Boston Edison now NSTAR
Don - I don't think you are nit picking. On the contrary, I think you bring up some very good discussion points. As for insurance claims, anything can happen as far as them dancing out of paying something off. I offer the modification "as is" and on a "use at your own risk" basis. As far as circuit loading, it's interesting to see how the sub-panel breakers add up. There are three 15 amp circuits and one 20 amp circuit. That totals 65 amps. All of which are strapped to a 30 amp main. Strictly speaking this is an overloaded circuit or certainly the potential for one. But in actual usage things don't work out strictly as circuit breakers are sized. In my case, any overload or short circuit would pop the 15 amp breaker whether it feeds entertainment, frig or both. Thus the circuit if protected adequately. It's really no different than plugging two hair dryers into a duplex outlet. The result would be a popped breaker.
We had concerns about the insurance BS when we had a house. You'd do work yourself in either areas of electrical or plumbing. Obviously following safety procedures and good construction practices. But homeowners (like my self) aren't licensed electrician or plumbers. So when your house burns down because of a chimney fire, the insurance company cancels your insurance because your kitchen duplex outlet wasn't installed by a licensed electrician. And it's an issue no doubt.
Personally I think education and working with projects promotes safety by making people more aware of issues. It also keeps people better informed about their surroundings. All of which are a perk to safety IMHO. But it's a crazy world out there and anything can happen. As for me, I'm a DIYer going way back and that's not likely to change anytime soon. I'll continue to offer my experiences to the group with the hopes it is helpful. Read what you want, be inspired or simply hit the delete key. Thanks for the comments, however. Something that never crossed my mind. And you learn a thing or two new everyday.

At 01:46 PM 10/24/2012, you wrote:

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: Hi Folks, : : I read Scott's description of the adjustments he has made to allow running his Norcold on the inverter. As usual Scott is very inventive and an good writer. However in this case I think there is something that Scott has failed to address, no offense intended Scott. : : I didn't see any attempt to address whether or not his recommended circuit changes meets the RVIAA electrical code. I am not completely familiar with the RVIAA code but suspect that like most electrical codes it closely follows the Nation Electric Code. I don't believe that any code would allow piggy backing a 20 amp circuit off the load side of a 15 amp breaker and bypass it's own 20 amp breaker. There is more to sizing breakers than simply adding up the expected ampere load on a given circuit. There are other issues as well. : : Before you all jump down my throat for nit picking Scott's idea, that is not what I am trying to do. It is the issue of insurance. If something electrical goes wrong causing electrical damage to the coach the insurance company is going to go over the entire coach with a fine tooth comb looking for anything that is not done to code. They will use any excuse they can to not pay off. As far as I know it is still ok to do your own wiring in your own house but it still has to be done to code. : : I am not going to attempt to evaluate the risk here I will leave that to each individual. I only want to point out that is does exit in my opinion. : : Don Seager : 2004 Allure 31046 :

: Best - Scott : 2006 Allure 430 40' #31349 : (Bus-Stead Lemon) My Allure Page http://www.muniac.com/Allure%20Page.html:

Best - Scott

2006 Allure 430 40' #31349

(Bus-Stead Lemon) My Allure Page http://www.muniac.com/Allure%20Page.html