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I'm having central air/heat installed in my 2003 Catalina 28 and I have a question about whether or not I need to have a second 30 amp shorepower installed. I'm getting a 9,000 BTU Mermaid unit that will take about 9.1 amps to run and expect that I will be using the hot water heater at times the AC is running. I'm waiting for a call back from Catalina but wanted to get opinions of other who have AC and whether or not I should have the second 30 amp installed. Thanks!
Should be OK /w single 30A
A single 30A 120V inlet may suffice, provided you don't have many additional (undisclosed) loads. The Hot Water Heater, if 1500 Watt, will draw about 13 Amps - and if 2000W, about 17 A. AC @ 9A + HWT @ 13 = 22 A AC @ 9A + HWT @ 17A = 26A You'll probably want to start the Air-Cond. with the HWT Heater "off" (motors have very high starting currents), then turn the HWT back on after AC running. Gord
A single 30A 120V inlet may suffice, provided you don't have many additional (undisclosed) loads. The Hot Water Heater, if 1500 Watt, will draw about 13 Amps - and if 2000W, about 17 A. AC @ 9A + HWT @ 13 = 22 A AC @ 9A + HWT @ 17A = 26A You'll probably want to start the Air-Cond. with the HWT Heater "off" (motors have very high starting currents), then turn the HWT back on after AC running. Gord
Shorepower and AC
My Hunter has two 30 Amp shorepower connections but I only use one. My A/C is a 14,000 BTU unit and on its own bus. I can parallel the two 120v AC shorepower busses at the breaker panel. My hotwater heater is always on. The only time I have a problem is occasionaly the Air Conditioning breaker trips when the compressor starts up and the microwave happens to be on.
My Hunter has two 30 Amp shorepower connections but I only use one. My A/C is a 14,000 BTU unit and on its own bus. I can parallel the two 120v AC shorepower busses at the breaker panel. My hotwater heater is always on. The only time I have a problem is occasionaly the Air Conditioning breaker trips when the compressor starts up and the microwave happens to be on.
SOUNDS DANGEROUS *box
Marc, I do not know exactly how your system is configured but it sounds to me like you have a shocking potential (no pun intented). If you can parallel the boat end of the two shore power cables, then the extra male plug (either on the boat or cable end) is hot and just waiting to bite someone that does not know what the situation is. Most knowledgeable marine electricians will not set up a dual 30 amp system like you describe.
Marc, I do not know exactly how your system is configured but it sounds to me like you have a shocking potential (no pun intented). If you can parallel the boat end of the two shore power cables, then the extra male plug (either on the boat or cable end) is hot and just waiting to bite someone that does not know what the situation is. Most knowledgeable marine electricians will not set up a dual 30 amp system like you describe.
I have (2 ) 30 amps
and I have a Hunter 28! I think you need two! Think about it... battery charger, microwave, hot water heater, TV, lights, frig.... Good Idea.. and then your going to need the 50 amp convertor another 250 buck.... Yes my friends boats are nothing more than a hole to pour your money!
and I have a Hunter 28! I think you need two! Think about it... battery charger, microwave, hot water heater, TV, lights, frig.... Good Idea.. and then your going to need the 50 amp convertor another 250 buck.... Yes my friends boats are nothing more than a hole to pour your money!
Marc, pay for the extra feed
unless your in a 50 amp service pay for the extra 30 amp feed or you'll be sorry!
unless your in a 50 amp service pay for the extra 30 amp feed or you'll be sorry!
30 amp here
I have a 16,500 BTU A/C and have not noticed any problems while using 30 amp service even with the water heater and battery charger. The wires and cord are still cool to the touch and no breakers have been thrown. All other devices aboard are 12V. Don't short change yourself when selecting a wire gauges. Jeff
I have a 16,500 BTU A/C and have not noticed any problems while using 30 amp service even with the water heater and battery charger. The wires and cord are still cool to the touch and no breakers have been thrown. All other devices aboard are 12V. Don't short change yourself when selecting a wire gauges. Jeff
Tie Breaker
Frank is right about he possible dangers of AC “Tie Breakers”. A inadvertantly live (unused)inlet is very dangerous!!! There is one possible solution to the ”Live Inlet” hazard: The “Tie Breaker”, that parallels the two 120V AC Services can be “Interlocked” with the Breaker Protecting the unfed inlet, so that only one can be “On”, thereby preventing a backfeed from the connected inlet to the unconnected inlet. The Tie Breaker and Service Breaker are (physically) Side-By-Side, and a “Lockout Slide Bar” (Blue Sea Systems #4125) prevents both breakers from being “On” at the same time. The Tie Breaker is wired to the “LOAD SIDE” of both 30A 120V D.P. Service Breakers. Please advise if this isn’t absolutely clear, and I will try again. Gord
Frank is right about he possible dangers of AC “Tie Breakers”. A inadvertantly live (unused)inlet is very dangerous!!! There is one possible solution to the ”Live Inlet” hazard: The “Tie Breaker”, that parallels the two 120V AC Services can be “Interlocked” with the Breaker Protecting the unfed inlet, so that only one can be “On”, thereby preventing a backfeed from the connected inlet to the unconnected inlet. The Tie Breaker and Service Breaker are (physically) Side-By-Side, and a “Lockout Slide Bar” (Blue Sea Systems #4125) prevents both breakers from being “On” at the same time. The Tie Breaker is wired to the “LOAD SIDE” of both 30A 120V D.P. Service Breakers. Please advise if this isn’t absolutely clear, and I will try again. Gord
I have a 12000 BTU
Mermaid with reverse heat, I have had no problems in two seasons,HWH, Battery charger, and other AC accesories running at the same time, breakers are all cool, along with power supply cord. I added the AC breaker to the existing AC fuse panel in an unused area.
Mermaid with reverse heat, I have had no problems in two seasons,HWH, Battery charger, and other AC accesories running at the same time, breakers are all cool, along with power supply cord. I added the AC breaker to the existing AC fuse panel in an unused area.
Your surveyor will be looking for two
You need to have enough capicity to handle it. We dont know the loads you have on the boat. but, if you plug in the charger and the pressure water and the water heater, you could have a big problem. The surveyor will almmost always expect two 30.s or one 50 on anything with a.c. installed.
You need to have enough capicity to handle it. We dont know the loads you have on the boat. but, if you plug in the charger and the pressure water and the water heater, you could have a big problem. The surveyor will almmost always expect two 30.s or one 50 on anything with a.c. installed.
Have the marina add another 30 amp connection
When 30 amps of power from the dock is all that's being supplied, 30 amps is all you're getting on the boat, no matter how you try to split it up. Wiring can overheat, appliances don't get full power, which can damage them...you can even create a power drop to other boats on the dock, causing "brownouts" that trip their breakers. In short, you're creating a fire hazard. It shouldn't cost you more than about $50 to have the marina run a second 30 amp circuit to your boat, on the same meter. Please do it!
When 30 amps of power from the dock is all that's being supplied, 30 amps is all you're getting on the boat, no matter how you try to split it up. Wiring can overheat, appliances don't get full power, which can damage them...you can even create a power drop to other boats on the dock, causing "brownouts" that trip their breakers. In short, you're creating a fire hazard. It shouldn't cost you more than about $50 to have the marina run a second 30 amp circuit to your boat, on the same meter. Please do it!
One more thing to remember...
is that N.E.C. and general good electrical engineering principals dictate that no circuit should be loaded beyond 80% of its nominal rating, so for a 30 amp circuit, max load should be restricted to no more than 24 amps. To go beyond that figure risks overheating, voltage sag and other problems that can then lead to equipment failure. It would be a shame to burn out the (expensive) compressor motor in your brand new AC unit because you scrimped on the required wiring for it. Just consider upgrading your shorepower system as a small price to pay for the comfort of AC!
is that N.E.C. and general good electrical engineering principals dictate that no circuit should be loaded beyond 80% of its nominal rating, so for a 30 amp circuit, max load should be restricted to no more than 24 amps. To go beyond that figure risks overheating, voltage sag and other problems that can then lead to equipment failure. It would be a shame to burn out the (expensive) compressor motor in your brand new AC unit because you scrimped on the required wiring for it. Just consider upgrading your shorepower system as a small price to pay for the comfort of AC!
My 2 cents
The starting current for your AC is 24 amps. Hot water Heater at 110 VAC (voltage drop from 120VAC for long dock run) 14amps. Battery Charger 30amp 12DC draws 8amps AC. If these are your only loads your are probably alright with a 30amp cord. My guess is if your are running the micro wave and or the hair dryer, and the compressor trys to start you are going to trip the breaker. The only way to safely add a second shore power cord is to have a system (it gets complicated) to split the buss and isolate the second shore power connection. For the price and your size boat, converting to 50amp shore power cable is the easiest. You still have the problem if you do not have 50amp service at the dock. The cheap solution is to install dedicated panel and 2nd 30 amp connection. With out lock out or correctly wired rotary switch, do not connect the buss.
The starting current for your AC is 24 amps. Hot water Heater at 110 VAC (voltage drop from 120VAC for long dock run) 14amps. Battery Charger 30amp 12DC draws 8amps AC. If these are your only loads your are probably alright with a 30amp cord. My guess is if your are running the micro wave and or the hair dryer, and the compressor trys to start you are going to trip the breaker. The only way to safely add a second shore power cord is to have a system (it gets complicated) to split the buss and isolate the second shore power connection. For the price and your size boat, converting to 50amp shore power cable is the easiest. You still have the problem if you do not have 50amp service at the dock. The cheap solution is to install dedicated panel and 2nd 30 amp connection. With out lock out or correctly wired rotary switch, do not connect the buss.
Another 2 cents
I agree with O_Salt, Gord May and others - Best thing is 100% engineered with lots of safety factor put in & to have 2 inlets and the 80% rule is a good one. But heck, if you don't close your through hulls every second and the hose breaks you could sink too? And to imply the boat is going to spontaneous combust unless you do this, is a little 'over the top'. The boats wiring shouldn't "burn up" if its correct and adequate gauge and installed properly. Thats why you have circuit breakers and protection circuits. I think it all depends on how often you plan on "overloading" the circuit. If your AC needs are typically low and the AirConditioner and maybe a few things are the only thing on you should be fine. Think about it, what's the difference between someone having a space heater plugged into your 110 VAC outlet on board to keep you warm in October? What's the difference between someone having a 1500 watt plugged into your 110 VAC outlet on board to blow dry their long blonde hair? The answer is nothing - (except the start up currents involved) but people do that EVERYDAY without thinking twice. In fact they have multiple things plugged into their outlets. (ed. note - not taking into account inductive loads etc.. lets keep this simple -- but I do understand the princple involved with throwing phases out) ps. I have one 120VAC inlet and I have a 16.5kbtu Flagship AC unit installed and it works fine. Yeah if I turn on and start up the Charger with a dead battery and I turn on the Hotwater heater and its water is cold and I turn on the Microwave AND I turn on the 16.5k btu AC unit it with blow the panel mounted breaker. Then yeah it would better to have 2 AC inlets but to say you can't do this safely out of hand is not telling the whole story BEWARE -- people with bad wiring and unprotected circuits should NOT do as I have done. In fact they shouldn't plug ANYTHING in !
I agree with O_Salt, Gord May and others - Best thing is 100% engineered with lots of safety factor put in & to have 2 inlets and the 80% rule is a good one. But heck, if you don't close your through hulls every second and the hose breaks you could sink too? And to imply the boat is going to spontaneous combust unless you do this, is a little 'over the top'. The boats wiring shouldn't "burn up" if its correct and adequate gauge and installed properly. Thats why you have circuit breakers and protection circuits. I think it all depends on how often you plan on "overloading" the circuit. If your AC needs are typically low and the AirConditioner and maybe a few things are the only thing on you should be fine. Think about it, what's the difference between someone having a space heater plugged into your 110 VAC outlet on board to keep you warm in October? What's the difference between someone having a 1500 watt plugged into your 110 VAC outlet on board to blow dry their long blonde hair? The answer is nothing - (except the start up currents involved) but people do that EVERYDAY without thinking twice. In fact they have multiple things plugged into their outlets. (ed. note - not taking into account inductive loads etc.. lets keep this simple -- but I do understand the princple involved with throwing phases out) ps. I have one 120VAC inlet and I have a 16.5kbtu Flagship AC unit installed and it works fine. Yeah if I turn on and start up the Charger with a dead battery and I turn on the Hotwater heater and its water is cold and I turn on the Microwave AND I turn on the 16.5k btu AC unit it with blow the panel mounted breaker. Then yeah it would better to have 2 AC inlets but to say you can't do this safely out of hand is not telling the whole story BEWARE -- people with bad wiring and unprotected circuits should NOT do as I have done. In fact they shouldn't plug ANYTHING in !
55% of boat fires are electrical in origin
According to BOAT/US insurance, "11% of fires are started in the boat's AC power system, frequently at the shore power inlet." If 55% of fires are electrical, that would make the AC power system the source of 20% of electrical fires.
According to BOAT/US insurance, "11% of fires are started in the boat's AC power system, frequently at the shore power inlet." If 55% of fires are electrical, that would make the AC power system the source of 20% of electrical fires.
AC/Shorepower
Thanks for all the information on this subject. I will be talking to the installer tomorrow. I have called Catalina and left messages asking for the factory recommendation but have not gotten a reply.
Thanks for all the information on this subject. I will be talking to the installer tomorrow. I have called Catalina and left messages asking for the factory recommendation but have not gotten a reply.
Tom, proof of what you say is on the fuse panel
of our homes. Open the panel and check out the main breaker. Mine's 200amps. Then total the capacity of the sub breakers. On my house, they total about 450 amps. Houses work because not everything runs at the same time. Of course boats are a little different in that we don't have 200 amp service. But what did 'Dirty Harry' say? "A man has got to know his limitations".
of our homes. Open the panel and check out the main breaker. Mine's 200amps. Then total the capacity of the sub breakers. On my house, they total about 450 amps. Houses work because not everything runs at the same time. Of course boats are a little different in that we don't have 200 amp service. But what did 'Dirty Harry' say? "A man has got to know his limitations".
Peggy thats true. Don't blame an air conditioner
installed on one 30 amp circuit. Blame that on bad wiring and unprotected circuits. If thats not up to spec and in good condition then ANY load is a hazard.
installed on one 30 amp circuit. Blame that on bad wiring and unprotected circuits. If thats not up to spec and in good condition then ANY load is a hazard.
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