installing a 6000 watt inverter

[Gone]

Re: installing a 6000 watt inverter

Think about this.
Obviously the inverter has an input fuse/circuit breaker. You MUST have the ampacity in the wire to sustain until the fuse blows in case the inverter stalls or exhibits a malfunction(typically 150% of rated fuse current for 30 seconds). You want the fuse to blow not have the insulation melt off and cause further problems. It's the whole basis for the code requirements.
You can do it half-@ss or do it right! As Dirty Harry would say: "Do you feel lucky?"

CD

 

[jason176]

Re: installing a 6000 watt inverter

You guys are killing me, look up ampacities in the code book. The ampacities are pretty much correlative to what size breaker you can land them on, of course there will be variances due to different types of insulataion have different ampacities. I am an electrician and have studied electricity all of my life, this isn't a hobby for me its my livelyhood. Since code was brought up we are now onto 120v wiring. Look at the inside door of your electrical panel and look at the fault current rating of your panel, it will be substantially higher than the normal operating current, but it isn't sized to handle fault current normally. I have only seen insulation melt off wire once and it was when a ground wire was tied directly to the hot. If the wire is sized too small the wire will heat up and you will have increased voltage drop (which is why you size wire), it will take a directly bolted short to melt insulation off wire. When it comes to fuses or circuit breakers for automotive applications, I try to use fuses when possible due to the fact that you aren't relying on a mechanical device to shut down the circuit, fuses will reliably trip when the threshold amount is exceeded everytime. Speaking of fuses what size are the fuses/circuit breakers on the inverter, you are correct on the fact that the wire should be sized to that but not peak power, I should have been more specific but in my experience it has always been relatively close.

@verycrustydude: I don't think there was any malisciousness in your "half-ass" comment but I can tell you I will sign my name on ALL of my work because I know its right and I can prove it with theory.

 

[ZmOz]

Re: installing a 6000 watt inverter

Speaking of fuses what size are the fuses/circuit breakers on the inverter, you are correct on the fact that the wire should be sized to that but not peak power

The fuses in the inverter are rated at the PEAK power, just like the cables should be. You just agreed with me right there. Yes, the fuses and cables should have the same rating, and that rating is 6000 watts, or 500 amps. Both of the wire size charts you have posted are completely worthless, the first doesn't go high enough and the second one doesn't specify length.

AMPLIFIERS ARE NOT INVERTERS! Inverter peak loads are alot different than amplifier peaks. Since you clearly have no experience with inverters, here's some important info for you to read:

http://www.solarseller.com/inverter_information_page_.htm

When you purchase the fuse or circuit breaker for your inverter,
check the surge input rating for the inverter.
If you don't, everything will be fine as long as you never draw more than the
inverter's rated continuous output.
If you ever have to start a heavy load and the inverter goes into its surge rated
output, the fuse or breaker will blow. Size the fuse or breaker for the surge
rating and you will not be dissapointed.

Here's info from the manual for a 2500 watt Xantrex inverter. This inverter is only rated at 5000 watts surge, so obviously the cables will be smaller than that needed for a 3000/6000 inverter.
http://www.xantrex.com/web/id/858/docserve.asp
Scroll down to page 24. There you will find a recommendation for 350 MCM size wire in runs up to 10 feet. That is sized for the PEAK load, by the manufacturer. Even 4/0 is not large enough for the 10-15 feet the original poster wants to run.

The fact that you are an electrician is totally irrelivant. Electricians do not install inverters, and you've already proven that you don't know how. I see people all the time who claim to be electricians, plumbers, mechanics, cops, lawyers, etc, giving absolutely horrible advice in the subject they claim to be an expert in. The advice you are giving here is UNSAFE, and goes against all manufacturer recommendations.

To the original poster:
Because of the ENORMOUS amount of amps your inverter can draw, you should not run the cables more than 5-10 feet. The best thing to do would be to install the inverter right next to the batteries and then run your 120v wiring wherever you need it.

 

[Gone]

Re: installing a 6000 watt inverter

{Quote}Because of the ENORMOUS amount of amps your inverter can draw, you should not run the cables more than 5-10 feet. The best thing to do would be to install the inverter right next to the batteries and then run your 120v wiring wherever you need it.[/quote]

First Rate advice, Oz!

No one is criticizing the 120V side, only the bad advice on the 12V side, Jason. Inverters are deceptive consumers of current, both at start-up and in failure mode. The current is lethal and the fire hazard is enormous. This is NOT the place to cut corners, especially in a boat.

Code doesn't have to be only NEC, as there are codes governing 12V in the marine, RV and automotive industries.

CD

 

[jason176]

Re: installing a 6000 watt inverter

Well you guys got me on the fuses, I got wrapped up in this whole peak power discussion. Common sense would tell one to rate the cable on the overcurrent protective device which I should have said from the get go. I must have missed where he said it had 500 A fuse. Since he stated that the manufacturer reccomended 2/0 no longer than 3 feet, I a$$-u-me-d the fuses were relatively close to 250 amps.And I know the first chart doesn't go that high I acknowledged that and the second chart you must specify the length and the calculator will do the work for you. Well, that is about enough back peddling for now.:$:$