Shore Power Inlet Plug Fire Hazard: Marinco vs. SmartPlug

thataway · Posted: Thu Dec 04, 2014 4:57 pm Post subject:

I have used "extension cords" in several small boats I have owned. There are some potential safety issues, and if the cord has a GFCI, then it is far safer. The current boat came with an extension cord and two cheap automotive trickle chargers. I pulled that out, and put in a very simple 15 amp system. There are two plugs (The entire circuit is GFCII protected)--one outboard and aft of the helm seat, and one at the foreword edge of the aft dinette seat. Three conductor vinyl sheathed Marine grade tinned wiring was used. I choose a 15 amp fuse/on/off switch designed for a heavy duty outdoor motor, rather than the fancy marine panel. I hard wired a MasterVolt 3 bank battery charger to this switch. The input is a Marinco 15 amp connection, which is in the outboard aft bulkhead under the gunnel. I use a 12 gauge wire heavy duty extension cord--a bit overkill.

If you want to run an extension cord for occasional use with a small heater, appliance or drill, then that works. But use a heavy cord and GFCI You can thread the cord thru the aft bulkhead by the galley, where the controls run. But I would prefer to have a proper inlet, some fuse or breaker protection, assurance that the cord would not be in the water, and a on/ off switch. if the cord is left on the boat for length of any time. Many outdoor extension cords are undersized for a full 15 amp circuit if you choose to use that and run a 50 foot cord.

colbysmith · Posted: Thu Dec 04, 2014 7:10 pm Post subject:

The "heavy" part is in the weight and size of the cords and connectors. In the end, and mostly for the reasons Will C discussed, I ended up installing the new Smart Plug system I bought. 30 amps is more than I will ever need, but since the system was already installed, which included some outlets, and I made the purchase of the new stuff, I went with it. That being said, if I did not have shore power already installed, and wanted to be able to power a battery charger and maybe one outlet, I would just go with the 15 amp service thru the hull connector. Unless one plans to use air conditioning, microwave, coffee pots, etc., 30 amp really is overkill on a CD-22. Colby

Will-C

I think typically breakers and electrical ratings are based on 75% of the expected amp draw. The way I envision it on a boat the 30 amps is like a 200 amp service coming into a house which is covered by the main breaker, then the individual items get covered by the smaller individual breakers with the smaller amp rating and wire size for each device. If you don't need shore power than you don't need shore power. My thoughts are to present the best advice in my opinion. For us which might be a different situation than most our boat is always plugged into shore power unless we are on the water or anchored. Since the examples show pictures of electrical fires caused in the area of the power inlet receptacle on boats the added insurance of a thermal breaker which opens the circuit I think is if nothing else a good reason to install a Smart Plug no matter what your amperage draw might be.
D.D.

colbysmith · Posted: Fri Dec 05, 2014 9:35 am Post subject:

The part about the thermal breaker has me wondering. I have looked at my new smart plug, male and female connectors, and read thru all the packaging and papers that came with it. I do not see any thermal breaker molded in or otherwise part of my Smart Plug system I have, not in the connector set, nor in the cord. It does speak of less heat generated because of more contact space. I'm wondering if you have a higher end plug that comes with thermal protection. Just as the female end that came with the connector set I purchased, did not have a light indicating power available, however the power cord I also purchased, did have the indicator light. To be quite honest, other than the contact space, I didn't see any difference in my original Marinco or this new Smart Plug. Well, except the boat recepticle is heavier with the Stainless Steel cap and base plate, as opposed to the all plastic of the Marinco. In fact, all the connectors from the old system were in very good shape with no indication of shorting or corrosion. Which reminds me, I now have a 50 foot Marinco 30 A cord for sale, $40, and a Marinco 30a Recepticle (boat mount) for $10. Any takers? Colby P.s. Buyer pays shipping.

thataway · Posted: Fri Dec 05, 2014 10:03 am Post subject:

Several comments: I agree with Dave 100% if the boat is going to be left plugged in. The thermal breaker is definitely an excellent addition. Also if there is going to be any current draw on peripheral sockets, a separate breaker for each circuit is necessary. (Often the peripheral circuits add up to more than the total input to the boat. For example C Dory factory wiring has a 30 amp main breaker, 15 amps on the several 15 amp plug in sockets, 15 amps for the water heater, 5 amp for the refrigerator, 5 amps for the battery charger (and in the case of the Tom Cat, I put in a separate 15 amp circuit for the microwave)

There is an interesting article, on the Smart plug site from a person who writes the ABYC standards:

http://www.smartplug.com/press_releases/Smart_Plug_Plea_Ed_Sherman_Editorial.pdf

He points out that one other main issue is with the shore power pedestal connectors--no thermal protection, and often are burned, with increased resistance etc:…

Will-C

I believe the thermal breaker is built into the boat socket part.
D.D.

colbysmith · Posted: Fri Dec 05, 2014 10:28 pm Post subject:

I just sent a msg to Smart Plug asking them about that Thermal Overload Protection. I also see it stated on one of their web page diagrams, but again did not see any apparent device when I installed the recepticle, nor is there any mention of it on the packaging materials. Bob, I do have the original factory installed shore power. It includes the main 30 amp double breaker (which allows both the neutral and the positive wires to be shut off) and three additional smaller breakers. One for my Battery Charger, one for the two outlets (1 under the dinette seat and one by the stove), and a unused spare. For my use, if I had not already had the 30 amp shore power service, 15 amps would have more than sufficed. Colby P.s. BTW Bob, yeah I have all kind of adapters also. Some I made, some I bought. Think I'm pretty well covered in that department! Smile

Aurelia · Posted: Fri Dec 05, 2014 11:16 pm Post subject:

The only available power near our boat at the Victoria BC gathering this summer was 20amp with the smaller twist connector. We do not carry that converter currently and just went without power for two nights. Didn't really matter to us then but I will find myself one before the spring.

Greg

colbysmith · Posted: Sat Dec 06, 2014 10:20 am Post subject:

That's one adapter I do not have either. I wonder if that is a Canadian thing. I've never seen that style plug anywhere else before.

Sea Wolf · Posted: Sat Dec 06, 2014 10:40 am Post subject:

Colby-

From my observations, the 20-amp twist-lock connectors are most commonly used around here (Northern California) by contractors on job sites.
I think they like the "stay connected"/no pull-apart, feature.

The prevalence of the use of one type or another probably varies by region, type of domestic, commercial, or industrial use, and by state regulations.

My guess, anyway!

I bought one of those large plastic milk carton containers full of different adapters from a retiring RV'er about 10 years ago.
Great buy, but I've never used, or even seen, some of the types of plugs in the container on a wall or pedestal anywhere.
But, following the motto, "Be Prepared" I'm still waiting! Laughing

Joe.

Larry H · Posted: Sat Dec 06, 2014 2:33 pm Post subject:

I have seen dock power in BC Canada that uses the 20 amp twist lock but supplies only 15amps. I think this is to have a 'locking' plug on a 15 amp circuit.

thataway · Posted: Sat Dec 06, 2014 2:43 pm Post subject:

Correct that the some Canadian Marinas have the 20 amp twist lock. I have also seen it in a few East Coast Marinas. I don't remember about marinas in N. Calif.

If you think the US is bad--try Europe (Australia and NZ and Asia also share many of these voltages, and also different plugs)--not only do they have entirely different power--including 50 hz, 230 volts, often 3 phase. There are also many different "plugs and sockets" We found out that the best way to deal with that, is to carry a pigtail which fit our 30 amp twist lock female fitting, and then put the adaptor for the local marine supply or hardware store onto this pigtail. I think we had over a dozen adapters when we were through. Also you had to understand the power and measure voltages, before connection and then at the female plug to be sure you had it correct. We also carried a 4KW transformer To convert 230 volts to 115 volts, which works for the battery charger and resistive heating loads. everything else was run off an inverter or by running the generator.

AK Angler · Posted: Sun Dec 07, 2014 2:37 pm Post subject:

colbysmith · Posted: Sun Dec 07, 2014 5:53 pm Post subject:

I think if Smart Plug wants their plug to become standard required equipment, then they need to be open to competition on the manufacturing of such a plug.

Sea Wolf · Posted: Sun Dec 07, 2014 9:15 pm Post subject: