AS Used Incorrect Wire Size, DC Fuse for Inverter

[TNOutback]

I am in the process of replacing the supplied AGM batteries with a pair of Battleborns and cleaning up the battery connections. Airstream used #4 AWG for the connection between the batteries and the Progressive Dynamics 1000W inverter, which I found odd. So, looking up in the PD manual, it clearly states the minimum wire size for the 1000W model with a 0-5 foot run is #2 AWG and #1 AWG for 5-10 ft. There is at least 10 feet of round trip wire run, so #1 AWG should have been used according to the manufacturer.

Airstream has also installed a 100 ADC fuse to protect the wiring, which is also undersized since 1000W/12V continuous amps x 1.25 safety factor comes out to 105 amps, which would mean a 150 ADC fuse should have been installed with a #1 AWG wire.

Are these warranty claims since both violate commonly accepted electrical code and the owner’s manual for the appliance?

[DCPAS]

Thanks for the info. I have an older version of the same trailer. How did you get to the converter? Through the circuit breaker panel or did you figure a way to remove the cushion bottom?

[TNOutback]

Originally Posted by DCPAS

Thanks for the info. I have an older version of the same trailer. How did you get to the converter? Through the circuit breaker panel or did you figure a way to remove the cushion bottom?

I have not accessed the converter. I was speaking about the wiring between the batteries and the PD inverter.

[skyguyscott]

Originally Posted by TNOutback

...Are these warranty claims since both violate commonly accepted electrical code and the owner’s manual for the appliance?

You would think so. I am almost certain, however, it would be grounds for a serious lawsuit, especially if it were to result in a fire. I would also be curious to see what sort of fuse is in the circuit and if that fuse is matched to the wire gage. I would bring these issues up with the dealer or the mothership should you encounter resistance with the warranty claim, insisting they install the correct cabling to standards. I can not fathom a good reason why it was installed the way it was. I can fathom some more likely reasons: ignorance, laziness, apathy, cost-savings, incompetence, negligence.

[DCPAS]

Originally Posted by DCPAS

Thanks for the info. I have an older version of the same trailer. How did you get to the converter? Through the circuit breaker panel or did you figure a way to remove the cushion bottom?

I appreciate that. I just figured you were changing the converter.

[ROBERT CROSS]

Originally Posted by TNOutback

I am in the process of replacing the supplied AGM batteries with a pair of Battleborns and cleaning up the battery connections. Airstream used #4 AWG for the connection between the batteries and the Progressive Dynamics 1000W inverter, which I found odd. So, looking up in the PD manual, it clearly states the minimum wire size for the 1000W model with a 0-5 foot run is #2 AWG and #1 AWG for 5-10 ft. There is at least 10 feet of round trip wire run, so #1 AWG should have been used according to the manufacturer.

Airstream has also installed a 100 ADC fuse to protect the wiring, which is also undersized since 1000W/12V continuous amps x 1.25 safety factor comes out to 105 amps, which would mean a 150 ADC fuse should have been installed with a #1 AWG wire.

Are these warranty claims since both violate commonly accepted electrical code and the owner’s manual for the appliance?

The operative word here is 'commonly'.
Good luck with a warranty claim without a 'failure'.

Sweet Streams...

[switz]

Make good records of your findings. Put the info in your legal documents. If the coach catches fire and folks die, the legal case for a claim against Airstream would be possible for intentional negligence on compliance with the National Electric Code.

[Glen Carter]

Are you saying 10' in each direction, 20' total wire....
in part it comes down to voltage drop... 4AWG works for 84A@20' with 4% drop .... If you are really needing the full 1000W from the inverter it might be marginal...

I find this helpful: https://www.explorist.life/wire-sizing-calculator/

[OrangeCrush]

Originally Posted by switz

Make good records of your findings. Put the info in your legal documents. If the coach catches fire and folks die, the legal case for a claim against Airstream would be possible for intentional negligence on compliance with the National Electric Code.

RVIA specifies electric requirements for RV's. NEC does not apply except NFPA 1192 which is only RV park wiring. They do reference ANSI low voltage spec which allows 10% voltage drop so 4 gauge wire is fine for a 1000 watt inverter. I agree it is inadequate as the inverter will drop out at max wattage when battery is low and cold, however, there is no code that requires it to be any more than 4 gauge. Bottom line is Airstream will probably not do anything about it and you have no legal recourse as it does meet RVIA specification.

[ITSNO60]

Originally Posted by OrangeCrush

RVIA specifies electric requirements for RV's. NEC does not apply except NFPA 1192 which is only RV park wiring. They do reference ANSI low voltage spec which allows 10% voltage drop so 4 gauge wire is fine for a 1000 watt inverter. I agree it is inadequate as the inverter will drop out at max wattage when battery is low and cold, however, there is no code that requires it to be any more than 4 gauge. Bottom line is Airstream will probably not do anything about it and you have no legal recourse as it does meet RVIA specification.

NEC does not even enforce voltage drop, it is just a recommendation in the fine print notes. They do however enforce that a product "must be installed in accordance with it's manufacturer's instructions". Does RVIA not have that requirement?

[OrangeCrush]

Originally Posted by ITSNO60

NEC does not even enforce voltage drop, it is just a recommendation in the fine print notes. They do however enforce that a product "must be installed in accordance with it's manufacturer's instructions". Does RVIA not have that requirement?

You have a good point and I don’t know the answer.

[jnm30327]

FWIW. This site shows DC voltage drop for 4 AWG wire for a one way distance of 4' and 80 amps at 0.20 volts.

[TNOutback]

Discounting the fact that the PD Inverter manual says the minimum gauge to use is #1 AWG for distances 5-10 feet, I referenced two separate wire gauge charts to validate the wire size. (Some sources dictate wire should be sized so that continuous current is no more than 80% of the wire rating; most add a safety factor of 25%, so 1000W/12V x 1.25 = 104 amps continuous max current with a margin of safety; otherwise 1000W/12V = 83.3 amps.)

The first is the ABYC E-11 charts, which stipulate round trip distance of the wire and 3% voltage drop for “critical” circuits (inverter, yes). The chart says #2 AWG should be used.

The second resource was a Voltage Drop Index where VDI = (83.3 amps x 10 feet) / (3% voltage drop x 12V) = 23.15 VDI. Per the chart for 23 VDI, it also stipulates #2 AWG.

[ITSNO60]

Originally Posted by TNOutback

Discounting the fact that the PD Inverter manual says the minimum gauge to use is #1 AWG for distances 5-10 feet, I referenced two separate wire gauge charts to validate the wire size. (Some sources dictate wire should be sized so that continuous current is no more than 80% of the wire rating; most add a safety factor of 25%, so 1000W/12V x 1.25 = 104 amps continuous max current with a margin of safety; otherwise 1000W/12V = 83.3 amps.)

The first is the ABYC E-11 charts, which stipulate round trip distance of the wire and 3% voltage drop for “critical” circuits (inverter, yes). The chart says #2 AWG should be used.

The second resource was a Voltage Drop Index where VDI = (83.3 amps x 10 feet) / (3% voltage drop x 12V) = 23.15 VDI. Per the chart for 23 VDI, it also stipulates #2 AWG.

The 80% and 125% rules are a little confusing as they mean the same thing. Sizing a circuit at 125% of the load or loading a circuit to only 80% nets the same result.

[OrangeCrush]

TNOutback - I think you should contact Airstream directly about your finding as you have a valid point that PD recommends larger wire than 4 gauge. Our 2017 came with a WFCO 1000W inverter and they recommend minimum of 4 gauge. I am guessing Airstream changed to Progressive Dynamics at some point and never looked at what their recommended wire gauge is and just left it the same. It would be good to point this out to them and you will change yours anyway when you install a Multiplus.

[dznf0g]

Don't think AS is the only one. I am doing some solar upgrades on my son's new (Australian) camper. It came with a 1500 watt inverter and has 7gauge wiring on the 12V input side (yes, 7 gauge???? An Australian thing???). The wire gauge chart says it should be, at a minimum 2 ga for the 5' round trip. In addition, there were no fuses on the (3) battery positive cables, nor on the inverter positive.

Am I missing something here?

[TNOutback]

Originally Posted by ITSNO60

The 80% and 125% rules are a little confusing as they mean the same thing. Sizing a circuit at 125% of the load or loading a circuit to only 80% nets the same result.

Correct. Same principle two ways to get there.

[Al and Missy]

Originally Posted by dznf0g

Don't think AS is the only one. I am doing some solar upgrades on my son's new (Australian) camper. It came with a 1500 watt inverter and has 7gauge wiring on the 12V input side (yes, 7 gauge???? An Australian thing???). The wire gauge chart says it should be, at a minimum 2 ga for the 5' round trip. In addition, there were no fuses on the (3) battery positive cables, nor on the inverter positive.

Am I missing something here?

According to this chart, there is a 7 AWG wire, as you might imagine, between 6 and 8. I had no idea.....

https://www.powerstream.com/Wire_Size.htm

Is the inverter an inverter/charger? If not there is no need for a fuse on the positive. Fuses protect the wire and should be as close as possible to the source of current.

[dznf0g]

Originally Posted by Al and Missy

According to this chart, there is a 7 AWG wire, as you might imagine, between 6 and 8. I had no idea.....

https://www.powerstream.com/Wire_Size.htm

Is the inverter an inverter/charger? If not there is no need for a fuse on the positive. Fuses protect the wire and should be as close as possible to the source of current.

It is a stand alone inverter with a separate charger and ,of course, a separate transfer switch. It's about a 6' round trip to the shunt and battery terminal. I would assume the inverter has internal protection, but I can find little information online about it. Typical oem overseas unit. I'd feel better with a fuse.