Shore power cord recommendation

[rbk]

Consider swapping one of what I assume are your basic ceramic fan heaters, for an oil filled radiant heater. These draw the same 1500w during heat up but once at temp require much less power to keep them going and are much safer than the fan type.

[SVTatia]

Originally Posted by donradcliffe

Two heaters on Marinco 30 amp plugs is a proven recipe for a disaster. You would be safer heating with a Buddy propane heater plus a CO alarm.

Really? How can a self-contained propane heater in a totally enclosed/closed up boat be safer than having a breaker tripped? Would you trust your life 100% to an electronic sniffer?

[MicHughV]

my advice is simple....you have three options.....either get a heavy duty 50 amp cord, with a splitter on the end....or use two 30 amp cords....

or, back the boat in, so you have a shorter run to the pedestal...and you could get away with a 25' -30 amp shore power cord....maybe....I'd still use two cords....two -25 footers...one for each heater...

regardless, I would use the heaters on their lowest setting......it's a fire hazard.

[mcon12000]

This isn’t that hard if you’re already comfortable with running the heaters you’ve chosen.

Since this new circuit is no longer powering the vessel and it is essentially a construction site temporary power run just build what’s needed.

L5-30 male plug attached to the necessary length of 12awg three conductor SO cable. This terminated at a small plastic distribution box with two 15amp breakers (you can go smaller 10amp). These feed two separate Edison GFCI outlets that your heaters plug into.

Please be aware that pedestal outlets and boat inlets overheat and burn due to poor wire terminations. It’s rarely caused by the blades or wipes of the plug provided they are nickel plated for marine use. It’s all about securing the wires properly and if this cable I’m suggesting you build where powering your actual boat’s system I would advise you to buy a factory assembled cable. With that in mind it wouldn’t hurt to modify an existing shore power cable to further insure that a poor termination on the L5-30 male doesn’t cause an issue at the pedestal.

[David Mathis]

You may have noticed that appliances require more amperage for start up than when running. Although you may be able to run both from a 30amp dock power tower (several other posts address this issue), if you're away for a few days, the temperature drops, and both heaters come on at the same time, they may or may not trip the breaker which could have obvious consequences. it's a risk depending on the type of heater, starting amperage, and running amperage.

The recommendation is to fix the electrical system on the boat then run one heater on the boat's system and the other separately from another tower, or from the 20 amp outlet on the tower.

[darylat8750]

If you look at farm supply type places 10 gauge extension cords are available. I would run one heater from one of those plugged into the 20 amp outlet on the dock. Use your 30 amp cord to a temporary box with a GFI for the other heater.

[deblen]

Consider using a 750watt 120vac heater-one in each hull.

Check with your insurance co. Mine does not allow any kind of heat while boat is "stored" off season.
Why do you want heat if you have winterized & will not be using boat?
Cheers/ Len

[tomrealest]

https://wardsmarine.com These are the best Marine Electric people, period. Call them and do what they say. Your life and boat are worth saving i would think. Electricity on a boat can be a recipe for a disaster if you don't know what you are doing.

[chasfgr]

Originally Posted by scarlet

Right idea.... But my concern with that is that I would have to use regular extension cords and you aren't supposed to use regular extension cords with heaters because they get so hot..

If it's getting hot, it's undersized - I prefer 16 amp plugs into 10mm 3 core cord, allegedly good for 80 amps.
I've only occasionally used two heaters, total about 6Kw, and found you need two plugs (and two jumpers), because the sockets start to smoke.
The outside temperature was reaching -8C during the night and there was ice forming on the marina surface.

[nonav]

The rule of breakers, or fuses, is you should draw no more than 80% of the load capacity of the breaker.

As for extension cords?

A shore power cable IS an extension cord, albeit a heavy duty one.

A 10 gauge conductor is rated up to 30A, 8 gauge up to 50A.

There are twist lock to “Con Ed” (standard) female electrical connectors.

Always good to have at least one in each sex.

Also a 50A to 30A adapter, and opposite come in handy.

Remember to use weak link as the max load capacity.

A 10 gauge adapted to a 50 amp tower, is best to pull around 24-25 amps, which is 80% of 30A.

This keeps you in safe parameters.

If unsure, feel the connectors after a little while.

A little warm, okay, HOT is bad!

[ayates]

Originally Posted by nonav

A 10 gauge conductor is rated up to 30A, 8 gauge up to 50A.

Remember that this is dependant upon length as well. For example, a cable carrying 30A for 100' needs to be 8 gauge.


Allan.

[mitiempo]

Originally Posted by nonav

A 10 gauge conductor is rated up to 30A, 8 gauge up to 50A.

50 amp shore power cables are 6 awg - as is the wire from boat inlet to AC panel.