electric upgrade help

[Pascal]

chris,

on the 53, all four ACs are on one leg while the rest is on the other leg. in typical use, I'm close to 50amps on the AC side, and arond 10 to 20 amps on the house side...

at somepoint, someone moved one of the AC on the house leg as i guess the four 16k units plus the pump must have been too much together...

[UNIQUE_NAME]

i'm running an old onan 6.5. i've had both a/c's, hot water heater and misc cabin stuff running on it at once, just once though....

[Hattenuff]

I had a similar problem on previous boat. One factor was overload on the circuit when block heaters kicked in. But I also found that the spring tension in the fuse holders had deteriorated and there wasn't good contact any more. Make sure this isn't adding to the resistance. Circuit breakers would be the way to go if you can avoid water exposure

[mstailey]

Jim,
Unless I mis-read your post (runs fine on the gen), you have your answer. Kind of. I'm by no means an electrical expert (lord knows I've posted enough electrical questions here) but I'd start at the source and work toward the boat. It has been my experience though that 80+% of my past electrical problems have originated from the source (marina).

What I do know for sure about electrical systems is if you start trying to re-engineer what Hatteras did for your boat you can get youself into big trouble.

I have the inline fuses with 2 30 amp 120v system like yours. Both of my A/C's and other ship services runs fine with no problems.

Anyway, that's my .02 worth.

[Boss Lady]

chris,

on the 53, all four ACs are on one leg while the rest is on the other leg. in typical use, I'm close to 50amps on the AC side, and arond 10 to 20 amps on the house side...

at somepoint, someone moved one of the AC on the house leg as i guess the four 16k units plus the pump must have been too much together...

I would obtain the Hatteras schematics and check your wiring against the original design. I have seen some pretty ugly stuff done. If you are pulling 50 amps on one leg, you cannot really have any other loads on that leg or you will trip a breaker. Your system was originally designed to have all loads balance between the two legs (110 circuits). I have seen a few boats rewired so that if you only have one connection at the marina shore power, the most used items have power, this is why you see all the air conditioner loads on one circuit. This is ok if you don't exceed the breaker capacity, but you canno t turn anything else on that is attached to that circuit without tripping the breaker.

[Maynard Rupp]

Our 1986 36C has 2 seperate 30 amp shore power receptacles. One is for the house and the other for AC. We have 2 Cruiseair units, one is 16000 btu, the other is 10000 btu. Our boat also has those old barrell fuses in screw top capsules just below the power receptacles. We have had lots of heat in the fuse holders and on occasion, (more often than I like), blown or cooked fuses. We also show about 28amp. draw on the Hatteras gages when both units are running. I am not sure what the gen set loads are. I know that heat is caused by resistance and have replaced the power cords. I have also removed the entire receptacle panel and cleaned and tightened all the wire hookups as well as cleaning inside the fuse holders. Keep in mind that our boat has never seen salt water so there isn't any obvious corrosion. It seems better now, but still seems to get warm. Because we are moving the boat to Florida, I am getting more AC concious. We just don't use it that often in the Great Lakes. The reverse cycle feature is very important in spring and fall.

[Boss Lady]

You need to boil out your A/C heat exchangers on occasion. The marine fouling will reduce the capacity and they will be operating at higher pressures, which can cause increased current demand (heat) in the wiring. I bought modern A/C units from Ocean Breeze Air Conditioning. Electronic controls and all, plus they have heating elements instead of reverse cycle, which works much better here in North Carolina. The price was fantastic and everything was stainless and cupronickel (commercial grade stuff, instead of the normal junk) You can look them up on the web.

[SeaEric]

I went to leave the slip one summer day 2 years ago and realized that my 30 amp cord, the dedicated air conditioner service, was welded to the inlet. Not only was the inlet melted, the wire to the panel was also fried for about 3 ft. Not good. The 30 amp was not sufficeient to run the 2 air units at once. The "house" feed was a 50 amp 125 that was pig tailed down to 30 amp 125, as 50 amp 125 does not seem to exist in marina power-dom.

What I ended up doing was to convert the system to run on a single 50 amp 250 cord and inlet, which we break in half on the panel. Now I have each air conditioner on it's own leg of the 50 amp. No more problems. I balanced out the rest of the house load over the 2 legs and have meters to monitor amperage use. It works very well now and I have much less worry about an electrical meltdown. While we were at the redo, I also had a custom engraved panel done that is all back lit. Its awesome, and so was the bill. The qoute was $3500 to $5000. and the final bill was $14,000. In fairness, we added a few "while you're in there's" and other extras, but it was still painful.

[Boss Lady]

I am in the middle of completely new wiring. I am converting to 24v and 12v DC as well. This is easy since all the old wiring is gone now. All the equipment will be load balanced between the two incoming 110 source power circuits. The generator will be happier too, since there will be equal loads. I have only seen 50 amp service in one marina and it is brand new and targeted to mega yachts. They also charge mega-yacht prices! I am installing an 8kw Northern Lights genset, which has reserve power even with everything turned on at once. I do not have a conventional oven, or washer/dryer, so the loads are not heavy.