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Old 10-20-2021, 08:34 PM   #10
catalinajack
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City: Edgewater, MD
Vessel Name: Catalina Jack
Vessel Model: Defever 44
Join Date: Nov 2011
Posts: 3,585
Quote:
Originally Posted by Portage_Bay View Post
OP If you haven't already got a decent meter I suggest something like this AC Digital Multi-Function Meter with Alarm. Put it on the input feed to your main AC panel and at a glance now how much power you are drawing. You can view AMPs, WATTs and Volts. I use the AMP display. Very easy to install. Not too expensive to hire a pro if you are unsure of your marine electrical skills.

I said elsewhere to you that you should not go above 24 AMPs continuous on your 30 AMP shore power service. That's 80% of 30 AMPs. I got that advice from someone far more knowledgeable about marine electrical systems than I. Your boat's 30 AMP system was designed to withstand 30 AMPs peak. Your shore power is essentially a extension cord. One that has been exposed to the marine environment. There will be resistance due to corrosion, looseness of the plugs due to wear and tear. Resistance will cause among other things heat, that's where the fire risk comes in. You have a CHB, likely 30 - 40 yrs old. Unless the electrical system has been re-wired there will be resistance aboard the boat as well.

Do be careful. I've lived on 30 - 40 yr old boats in your climate with 30 AMP service. It's far too easy to stress the system beyond safe levels especially in winter. I rewired one of them and as I pulled the out wire out I found places where it had gotten so hot the insulation was cooked. I found a lot of corrosion as well. Don't take chances.
Portage Bay, that link to the meter got me to thinking that I might benefit from having it. Then I realized that I already have two Blue Sea analog ammeters aboard, one for each of the two 50-amp legs, in my easily-viewed breaker panel. I can attest to their utility to monitor electrical demands. I do not let the draws exceed 45 amps. I did have to move the water heater feed to the other bus to better balance loads. I am now able to run two 16,000 btu ACs, the water heater, the battery charger, and house loads other than the cooktop or microwave without exceeding 40 amps on either side. Turning the water heater off allows all other draws. The point is, an ammeter is very useful as stated.
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