What AWG for 120 V inlet?

[BAD ORCA]

Curious what AWG triplex you guys are using for 30 amp (or 50) shore power inlet to AC distribution panel?

My current (original) i think is 10AWG which im replacing soon. All the online calculators are suggesting anywhere from 10-6 AWG. I think im going to go with 8. I have 30 amp shore with about 25 foot cable run one way. That should give me about 2% voltage drop give-or-take.

Just curious what some of you are using and if you have upgraded to heavier gauge for the lowest possible voltage drop now that lithium makes heavier electric appliance use more common, or if a few percent voltage drop really matters all that much on the AC side?

[GordMay]

#10 AWG Cu. wire is good for 30Amp, and, at 120VAC, voltage drop won't be a problem, at any reasonable distance.
Nothing wrong with oversize, except cost, weight, and difficulty installing.
For instance: The terminals, on your shore power inlet are designed for #10, so a larger wire would have to be trimmed, to fit. Same at shore connector.

[s/v Jedi]

I use 8 AWG for 30A circuits and 6 AWG for 50A circuits.

It is true that 10 AWG can do a 30A circuit but after the shore cables, which are long and 10 AWG as well as questionable outlets/inlets/plugs, creating a low resistance path inside the boat is simple.

[BAD ORCA]

Originally Posted by GordMay

#10 AWG Cu. wire is good for 30Amp, and, at 120VAC, voltage drop won't be a problem, at any reasonable distance.
Nothing wrong with oversize, except cost, weight, and difficulty installing.
For instance: The terminals, on your shore power inlet are designed for #10, so a larger wire would have to be trimmed, to fit. Same at shore connector.

Thanks Gord. I think im good and wont have to trim anything. I can get 8 gauge ring terminals or even power lugs to fit everything except possibly the shore power inlet plug as you mentioned. I will have to double check my power cord inlet and see if i can make it work without trimming any wires.

[BAD ORCA]

Originally Posted by s/v Jedi

I use 8 AWG for 30A circuits and 6 AWG for 50A circuits.

It is true that 10 AWG can do a 30A circuit but after the shore cables, which are long and 10 AWG as well as questionable outlets/inlets/plugs, creating a low resistance path inside the boat is simple.

Thanks Jedi. I'd rather spend the little extra money now and oversize it a bit especially since i will have half the galley torn apart to install it. I would like to run some energy hog items like an induction cooktop or burner in the future so i think it would be nice to know my mains cable can take everything i can throw at it and more.

I can imagine many modern boats with lithium must be pushing near 20+ amps regularly on a 30 amp circuit.

[s/v Jedi]

Originally Posted by BAD ORCA

Thanks Gord. I think im good and wont have to trim anything. I can get 8 gauge ring terminals or even power lugs to fit everything except possibly the shore power inlet plug as you mentioned. I will have to double check my power cord inlet and see if i can make it work without trimming any wires.

Wait a minute…. the first thing the shore power inlet needs to connect to (within a very short distance) is a double pole breaker. Use 10 AWG for that, then continue with 8 AWG.

If you don’t have an isolation transformer then this breaker must have a RCD protection too.

[rslifkin]

The common standard would be 10 AWG for a 30A inlet, 6 AWG for 50A. No reason not to go bigger if you want to reduce voltage drop and have more safety margin.

[BAD ORCA]

Originally Posted by s/v Jedi

Wait a minute…. the first thing the shore power inlet needs to connect to (within a very short distance) is a double pole breaker. Use 10 AWG for that, then continue with 8 AWG.

If you don’t have an isolation transformer then this breaker must have a RCD protection too.

I will have a Blue Seas double pole breaker about 5 feet from the shore inlet plug. From there it will go to a galvanic isolator about three feet from the breaker, then it goes to the distribution panel onto a Blue Seas ELCI breaker, then from the ELCI breaker to the main 120 panel right next to it. The Main 120 panel has no breaker, just switching, (see pic). I think that covers everything?

[boatpoker]

You probably know this already but just in case ... DO NOT use solid core copper wire from your local building supply outlet. Use stranded cable that meets UL 1426 available at almost all chandleries.

[s/v Jedi]

Originally Posted by BAD ORCA

I will have a Blue Seas double pole breaker about 5 feet from the shore inlet plug. From there it will go to a galvanic isolator about three feet from the breaker, then it goes to the distribution panel onto a Blue Seas ELCI breaker, then from the ELCI breaker to the main 120 panel right next to it. The Main 120 panel has no breaker, just switching, (see pic). I think that covers everything?

Okay for all those short distances you can simply use 10 AWG.

You have installed too much! Here is what to do:

From inlet to ELCI breaker. Remove the double polebreaker. Then you insert the galvanic isolator in the ground conductor and hook up to the 120 panel.

You don’t have an inverter/charger?

[BAD ORCA]

Originally Posted by boatpoker

You probably know this already but just in case ... DO NOT use solid core copper wire from your local building supply outlet. Use stranded cable that meets UL 1426 available at almost all chandleries.

Thanks boatpoker, nope i have been reading my ABYC manuals :P. Only tinned copper Ancor wire.

[BAD ORCA]

Originally Posted by s/v Jedi

Okay for all those short distances you can simply use 10 AWG.

You have installed too much! Here is what to do:

From inlet to ELCI breaker. Remove the double polebreaker. Then you insert the galvanic isolator in the ground conductor and hook up to the 120 panel.

You don’t have an inverter/charger?

I should have added that the wire run from the galvanic isolator to the elci breaker at the distribution panel will be about 15 feet of wire. don’t i need the double pole breaker first since it’s further than ten feet from shore inlet? total run is about 25’. nothing has been installed yet. still working on cabinet to house all the wiring but will be working on it during xmas break.

nope no inverter yet. i want to get the basics installed first and make sure everything is working the way it should. the inverter will be installed in a month or two down the road. i want to go slow and not overwhelm myself and make a dumb mistake by trying to do too much at once. i mean seriously, the manual for the BMV-712 alone is 60 pages. 😳

[s/v Jedi]

Originally Posted by BAD ORCA

I should have added that the wire run from the galvanic isolator to the elci breaker at the distribution panel will be about 15 feet of wire. don’t i need the double pole breaker first since it’s further than ten feet from shore inlet? total run is about 25’. nothing has been installed yet. still working on cabinet to house all the wiring but will be working on it during xmas break.

nope no inverter yet. i want to get the basics installed first and make sure everything is working the way it should. the inverter will be installed in a month or two down the road. i want to go slow and not overwhelm myself and make a dumb mistake by trying to do too much at once. i mean seriously, the manual for the BMV-712 alone is 60 pages. 😳

Ah okay, let’s see… can you replace the double pole breaker after the inlet with the elci breaker? As you don’t have an isolation transformer, you are required to have the elci. I went and looked it up and you are correct, you can keep it the way you have it.

So I would use 8 AWG for that long run.

BTW, for crimping 8AWG I use this crimper, which works very well: https://www.amazon.com/gp/product/B07WNVSMPN

[BAD ORCA]

Originally Posted by s/v Jedi

Ah okay, let’s see… can you replace the double pole breaker after the inlet with the elci breaker? As you don’t have an isolation transformer, you are required to have the elci. I went and looked it up and you are correct, you can keep it the way you have it.

So I would use 8 AWG for that long run.

BTW, for crimping 8AWG I use this crimper, which works very well: https://www.amazon.com/gp/product/B07WNVSMPN

oh nice. ordering a pair now. i have a couple iwiss ferrule crimpers and i really like them.

[s/v Jedi]

Originally Posted by BAD ORCA

oh nice. ordering a pair now. i have a couple iwiss ferrule crimpers and i really like them.

There’s a screw holding both parts of the crimper together. It can loosen, making the crimper twist. I used some threadlocker to prevent that.

I think I do two crimps per terminal.