Inverter installation question

[Streamin 65]

I recently purchased a Xantrex 1200 watt inverter to run a few things for when we decide to camp "cordless". The plan is to wire a receptacle (outlet) just below the breaker box and connect the inverter to that outlet via a small extention cord with two male ends to feed the circuit. The installation manual suggests a 150 amp DC fuse between the battery and the inverter. Although I'm sure it work with out the fuse, I'd really like to add one here just in case something were to short out. The problem I've had is some real difficulty finding a fuse that'll work. What I did find locally was an install kit for a 1500 watt car audio amplifier. It had the right size cable (2awg) and an inline fuse rated at 175 amp, however the fuse was an AGU not an ADC. Is there a difference? I mean, could an audio amplifier install kit work for a power inverter? Thanks, dave

[Tin Knocker]

Originally Posted by Streamin 65

connect the inverter to that outlet via a small extention cord with two male ends to feed the circuit.

There is a nickname for that- Deadman's Cable. Don't do it.

[Streamin 65]

Originally Posted by Tin Knocker

There is a nickname for that- Deadman's Cable. Don't do it.

May I ask why not? My thoughts were that a short legnth of 10 gauge wire (well, the left overs from the service change on the trailer) would carry the current just fine. Is there a good reason not too? Thanks, dave

[Alumaholic]

Originally Posted by Tin Knocker

There is a nickname for that- Deadman's Cable. Don't do it.

Dang it, Tin Knocker, you just eliminated another contender for the Darwin Awards.

[Alumaholic]

Originally Posted by Streamin 65

May I ask why not? My thoughts were that a short legnth of 10 gauge wire (well, the left overs from the service change on the trailer) would carry the current just fine. Is there a good reason not too? Thanks, dave

Yes, as Tin Knocker has already alluded, it could kill you or a family member in any number of accident scenarios. Your simple male to male connection defeats many decades of carefully developed electric wiring codes.

But on a lighter note, a female acquaintance upon learning that she could not run her microwave on the 12 volt system, responded that, "there should be a Federal law that all electricity has to be the same."

[Streamin 65]

Originally Posted by klevan

Yes, as Tin Knocker has already alluded, it could kill you or a family member in any number of accident scenarios. Your simple male to male connection defeats many decades of carefully developed electric wiring codes.

But on a lighter note, a female acquaintance upon learning that she could not run her microwave on the 12 volt system, responded that, "there should be a Federal law that all electricity has to be the same."

Not trying to discount anyone's advise against the male to male connection, but I still don't see how it could be a hazard. I'm not an electrical engineer or anything, but I was an electrician many moons ago, and my intuition is saying that it shouldn't be a problem at all, provided the correct gauge wire is used, unless the circuit was being fed by shore power and the inverter at the same time. I do know you can feed power to a house circuit in the same manner via generator provided the main breaker is off (to prevent backflow of power). Is there a solid reason that this setup would be unsafe? I build homes now for a living and have electrical inspectors on site frequently, I really inclined to get their opinion now!!! Thanks again, Dave

[markdoane]

Dave,

The first reason is that you have exposed, live conductors. Think "Tazer".

Other reasons are that you could plug the cord into two receptacles of different polarity.

And of course as you noted, you could backfeed from a generator into the power grid.

I know you don't anticipate doing any of these things, but what about your 8 year old child who doesn't know any better.

[Alumaholic]

Originally Posted by Streamin 65

I do know you can feed power to a house circuit in the same manner via generator provided the main breaker is off (to prevent backflow of power). Is there a solid reason that this setup would be unsafe? I build homes now for a living and have electrical inspectors on site frequently, I really inclined to get their opinion now!!! Thanks again, Dave

You've captured a couple of the lethal scenarios that I was contemplating.
When I lived in NC, we would have one or two linemen injured or killed each hurricane season when homeowners would hook up their house to a generator with a "Deadman's Cable." The correct design for your application would include a fool proof means of switching to inverter power that cannot be overlooked or forgotten in the haste to break camp and get on the road. Can you imagine the excitement you would have if you left your connecter plugged in from your last "cordless camp" and then hooked up to 120 AC at your next stop? Good luck with your design. I think it would be a great thing to bounce off your electrical inspector. Most would enjoy the opportunity to ensure a safe solution to your project.

[lewster]

This is what you need to do the install you are talking about. A manual transfer switch will allow inlet current from only one source at a time...be it the inverter or shore power. These are common on any RV that has a gen-set so that the generator current can't collide with the shore power, it's one or the other.

If you want to be totally certain that you will never have any of these scenarios, why don't you simply dedicate an outlet or two to the inverter ONLY. This way they will be dead when hooked to shore power and will be hot ONLY when you are using the inverter. No feedback, no connection to the 120VAC trailer wiring, NO PROBLEMS!

[Alumaholic]

Originally Posted by lewster

This is what you need to do the install you are talking about. A manual transfer switch will allow inlet current from only one source at a time...be it the inverter or shore power. These are common on any RV that has a gen-set so that the generator current can't collide with the shore power, it's one or the other.

If you want to be totally certain that you will never have any of these scenarios, why don't you simply dedicate an outlet or two to the inverter ONLY. This way they will be dead when hooked to shore power and will be hot ONLY when you are using the inverter. No feedback, no connection to the 120VAC trailer wiring, NO PROBLEMS!

And you won't have a Male-Male pigtail just laying around waiting for someone to pick up and curiously plug in to the nearest outlet and zzzzZZZAAAP!

[wkerfoot]

Originally Posted by lewster

This is what you need to do the install you are talking about. A manual transfer switch will allow inlet current from only one source at a time...be it the inverter or shore power. These are common on any RV that has a gen-set so that the generator current can't collide with the shore power, it's one or the other.

If you want to be totally certain that you will never have any of these scenarios, why don't you simply dedicate an outlet or two to the inverter ONLY. This way they will be dead when hooked to shore power and will be hot ONLY when you are using the inverter. No feedback, no connection to the 120VAC trailer wiring, NO PROBLEMS!

Lew,

That is exactly what I was considering when rewiring the 1954 Liner. Someone else thinks the same as me, scary.

Bill

[lewster]

Hey Bill,

I hear ya'! There are probably a bunch of members who think alike around here. Seem to be 'many' great minds on this forum!

[Streamin 65]

After quite a search to find the appropriate fuse for my inverter (Xantrex recommends 150 amp DC) and holder, I came across the perfect setup today at HH Gregg. They had an installation kit for a 3000 watt car audio amplifier on sale for $49. The kit consisted of 18' 1/0 AWG and 4' 1/0 AWG plus a fuse, fuse holder and some other stuff I really don't need (for now at least). The wire is larger than what Xantrex recommended (that would be 2 AWG), but what the hey, bigger is better when it comes to wire, and I got plenty to do the install for a great price. I just finished cutting the wire to legnth and tinning on the connectors. I'm adding a battery selector switch so I can have the system run off two batteries at the same time or just one at a time. Next step is to get some glass mat batteries. Anyone have an opinion for or against the optima blue top d31m? They are availaible (almost) locally. Thanks, Dave

[lewster]

Originally Posted by Streamin 65

After quite a search to find the appropriate fuse for my inverter (Xantrex recommends 150 amp DC) and holder, I came across the perfect setup today at HH Gregg. They had an installation kit for a 3000 watt car audio amplifier on sale for $49. The kit consisted of 18' 1/0 AWG and 4' 1/0 AWG plus a fuse, fuse holder and some other stuff I really don't need (for now at least). The wire is larger than what Xantrex recommended (that would be 2 AWG), but what the hey, bigger is better when it comes to wire, and I got plenty to do the install for a great price. I just finished cutting the wire to legnth and tinning on the connectors. I'm adding a battery selector switch so I can have the system run off two batteries at the same time or just one at a time. Next step is to get some glass mat batteries. Anyone have an opinion for or against the optima blue top d31m? They are availaible (almost) locally. Thanks, Dave

Optima's are OK but they have a limited capacity due to the shape. IMHO, the best AGM's out there are the Lifeline brand. If you really want the killer set-up, go for a couple of 6 volt Lifeline 4GC's in series. They have a better charge/discharge capacity than a 12V and will last you a long time. Better have a 3 stage charger to go with them also!!