How long of 50 amp cord is safe?

Charlesoceanone

Charlesoceanone

Well-Known Member
Dec 14, 2014
455
Harbor Shores Marina, St Joseph, Michigan
Boat Info
2013 58 Sedan Bridge
2021 Walker Bay LTE 11
Engines
Man 900
I have 2 slips end to end along a wall at my marina. I do not have power at the slip farthest from the pedestal and I am definitely not an electrician. Is it safe to run a 100 foot 50 amp cord that far? I did find one on the interweb but just because they sell it doesn’t mean it’s safe. Thanks.
 
It comes down to the size of the wires versus the power you try to pull through them. Since there's inherently some loss through copper wire (energy wasted as heat), then the longer the wire, the less power is available at the boat. To counter this, you need to up-size the wire as the length increases. For 50 amps at 100 feet, 6AWG would be the minimum. If you know you'll never use the full 50 amps, you could go smaller, but, you stand the chance of melting the cord if you try to pull too much current through it. 'Not worth trying to save a few bucks.
 
I do what Woody said except with 30 amp cords at times. Sometimes when traveling we bow in so we can use our dinghy and will run 100 feet of cord to reach the back of the boat where the connections are. Never had any problems.
 
As woody and my3sons said, it’s pretty common to have quite a bit out if you bow in. I would just try to limit the connections (as in two 50’ cords plugged together for long term use) but a 100’ 50A cord would be a beast to move around.

It’s likely you won’t need it for long!
 
As a reference I use a 100' 50a shore power cord at my permanent slip. I run just enough cord out of my cablemaster to hook it up near the platform. So that makes 175' of cord being used and everything works just fine. I can run all five AC units with no problems. That being said I would not make a habit out of toting that 100' cord around as its extremely heavy.
 
I guess you need to be careful on guessing that you won't use 50 amps. I am 50amp and I can use more then that if I'm not careful. Two AC units and the hot water heater put's me real close, use the cook top and microwave and your pretty much pushing the 50A mark if not over. I have N2K amp gauges that are pretty accurate. You might want to see what your actually drawing fully loaded so you can make a sound decision. Just my two cents.
 
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My normal use is 50ft (50 Amps) out of a glendinning at the stern. I do carry 2 50 amp cables that I can use from outlets on the bow if needed based on transient marinas. There have been times that I pulled out the 50ft cords and used them as an "extension cord", effectively a 100ft.

I watch amps (especially due to loads and the AC system in the summer) very closely at transient marinas - no issues running through 100ft.

Will echo the comment above, those cables are heavy. My experience is with a 50ft, 100 would be worse. I have moved to feeding the cable out of its storage location to someone on the dock rather than moving the container with the entire cable in it.
 
I do have a 50 footer I keep on the boat and I agree it is awkward to move around. I will not be moving this one it will stay at the marina For power to my second slip. Sounds like I’m good to go. They are expensive and have seen quite a range of prices. I just need to make sure to get the heavy wire.
 
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