I finished installing a new Atwood 15K BTU rooftop A/C last night. It ran fine for an hour or two. I started up the generator to make sure all three would run on the generator and they did. After about half an hour the breaker tripped for the Atwood A/C unit. Temps were only around 82 degrees and the sun was almost down so no real sun load.
Is this a sign my new rooftop A/C unit is bad if it trips the breaker at only 82 degrees? I have 12 gauge wire running to it and the breaker is 20 amp. My other two A/C units have run at 104 degrees outside (and tremendous sun load) without tripping the breaker.
If you don't have a clamp on ammeter to measure the current, I would replace the breaker. Relatively cheap way to troubleshoot and likely culprit.
If the breaker in ? has been tripped a bunch it could be weak link. Just a observation. They tend to get that way. FWIW.
They draw more than the 13 amps they advertize more like 16 to 17 about the same as a Coleman,it will blow cold air our friends have 2 in a S&S and were on 15 amp breakers it didn't work
I'm going to check for the amp draw later today. It would be cheap enough to get a new breaker although I've very rarely blown a breaker. I just rearranged all the breakers in the panel yesterday to accommodate the new A/C unit. I was trying to balance the load for when I run off a 240 volt circuit. (My generator is 120 volt and feeds both legs.)
I wouldn't expect any 15K BTU rooftop to work on a 15 amp breaker. All of my breakers are 20 amp (or larger as necessary).
Since they ran fine on shorepower but tripped breaker on generator power, you might check the voltage with the full load of all three running, with compressors engaged, and other typical loads on. If your generator can't maintain 120V under that load, then the amps would go up as the volts go down.
Remember that the maximum continuous current for a 20 amp breaker is 16 amps. Over that and it is supposed to trip after an hour or so particularly if it's installed in a hot location. I have read of 100% rated breakers being available. I was going to mention checking the voltage but got beat to it! ;D
Brian
Sounds stupid, but make sure the black wire coming from the breaker is tight. Vibration from running down the road can loosen it up causing heat and resistance. I installed a computer fan in my breaker box cabinet to cool it in summer. Good Luck, TomC
Tom,
It isn't just a loose black wire that can cause resistance, a loose neutral (white) wire can cause it too. I would be good to check all the wires in the panel for looseness.
Good luck, Sam
Correct, most 20 amp breakers are dual purpose, meaning both magnetic and thermally tripped.
Yes a 20 amp is actually 16 amp at most in a cool area. They can become maddening on a hot day with a large load that warms them up.
Dave M
The A/C was just wired up yesterday as it is now so I am pretty sure nothing is loose. The breaker could be bad perhaps. We are going to check the amp draw right now.
I haven't run it long enough on shore power to see if it trips the breaker on shore power too. It just happened to be running off the generator when the breaker tripped. I cannot run three A/Cs off shore power at home as I only have a 30 amp circuit.
I measured the amp draw on the new A/C and it is under 12 amps, but the outside temp is 75 degrees right now. I am running the A/C units all full blast to try to replicate the issues from yesterday. I even opened all of the windows to keep the A/C units running.
Does the breker trip within a few seconds or a longer time, if longer, you should detect with your fingers the breaker getting hot. If quick trip, would check the wiring again.
Dave M
Brian,
Just for giggles, if you connected the 12 ga wire from your 20 amp breaker to the air conditioner wires with wire nuts, and you reused the old wire nuts or too large new wire nuts, check those joints. They may be loose. Never re use wire nuts because the coil inside them can stretch and not make a firm connection. It is also a good idea to twist the wire ends together with a pliers and trim the ends even before putting the new wire nuts on. You get more contact between the wires that way. A few tricks I learned from my retired electrical contractor neighbor.
Good luck, Sam
This is a third brand new rooftop so I ran brand new wire for it. Atwood does not provide a junction box for the AC wiring so I used good quality butt connectors to connect their stranded wire to my stranded wire.
I have no idea if the breaker got hot as it only happened once. I tried to make it happen, but then my generator broke and I spent the rest of the evening fixing that.
Brian, you use insulated crimping sleeves for AC not a butt connector so I have been told over the years by the electrical guys
Hi Brian,
I am leaning towards what Hightech has stated.
Deff check your generator voltage on full load. If the voltage drops, the amp draw will go up.
I had a problem at the track today. The 50 amp breaker at the post I was plugged into tripped
several times. After eliminating my A/C's as the problem, I discovered my neutral connection
in my plug end was burning up. The loss or heating of the neutral connection was drawling
excessive power and exceeding the 50 amp breakers limits thus tripping it. I replaced the plug
end and the problem was solved. It had me scratching my head for a while but I'm glad I felt
the plug as it was very hot..
Good Luck
Nick-
I have some insulated crimping sleeves so I could redo the connection.
My generator voltage is between 113 and 114 volts with all the A/C units running. The voltage is about 126 no load. The load regulation is not the best, but I just put in a new regulator.
Quote from: luvrbus on July 13, 2013, 07:57:52 PM
Brian, you use insulated crimping sleeves for AC not a butt connector so I have been told over the years by the electrical guys
Quick nanosecond thread hijack here: Cliff, what are your thoughts or anyone's thoughts on an alternative to wire nuts? I have already had issues with my A/C and other wire nutted connections coming loose and causing issues. Honestly I'd like a better solution that's safer and I'll rewire our entire coach if its a reliable connector. Are these as good as they say?: http://www.posi-lock.com/posilock.html
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Quote from: Scott Bennett on July 14, 2013, 05:02:02 AM
Quick nanosecond thread hijack here: Cliff, what are your thoughts or anyone's thoughts on an alternative to wire nuts? I have already had issues with my A/C and other wire nutted connections coming loose and causing issues. Honestly I'd like a better solution that's safer and I'll rewire our entire coach if its a reliable connector. Are these as good as they say?: http://www.posi-lock.com/posilock.html (http://www.posi-lock.com/posilock.html)
I believe these are rated for automotive use per their own description.
I would not use them for AC circuits.
What's wrong with good old-fashioned terminal strips? Cheap, easy to use and secure, and used in all sorts of domestic and industrial OEM equipment. I've never understood the point of re-inventing the wheel with things like 'wire nuts', which I have always thought looked marginal at best (although I will admit to never having actually come across a wire nut in person, much less used one myself).
Jeremy
Jeremy, a question?
How are houses wired in UK? Are wire nuts not used for all the light-switch, receptacles and lights? Do you use terminal strips for this application?
Just curious,
GaryD
I'm 95% certain that wiring a house 'correctly' should never require any connections to be made other than those into the built-in connectors of the switches / sockets / light fittings etc. Having to join cables together at any other place would only happen if you'd cut the cable too short or something. There may be odd occasions (perhaps when a light is controlled by more than 3 switches) where there may a legitimate 'extra' connection to be made, and on those occasions I'm sure it would be correct to use a terminal strip connector (which do, after all, essentially replicate the built-in connectors in the sockets and switches etc).
My house is over 100 years old and when I bought it the wiring was probably 50 years old (stranded steel wire with fabric insulation etc). So, having re-wired the whole house myself, I think I know what good practice is from having always carefully followed instructions in DIY books etc, but I've certainly never had any official training so I've no idea what the 'code' says here about terminal strips vs wire nuts etc.
Jeremy
Jeremy, I sent you a private email.
GaryD
Here all connections are made in a junction box of some type,wire nuts are not that popular in new construction most contractors use insulated crimp sleeves in a J box,busse bars or terminal strips are not used except in the switch gear panel most of our stuff here is 110v
For the sake of my own curiosity I just did a quick Google and found this:
Why are wire nuts used in electrical work in US but not Europe?
In the UK they were generally called 'thimbles'.
They have been illegal here since sometime in the 50s.
Any joints have to have some definite mechanical connection & all forms of twisted wire joint were banned.
Any terminal or joint should have enough pressure to create a 'gas tight' connection between the conductors to prevent them oxidising at the point of contact, and a thimble does not create sufficient pressure to do that.
If the wires oxidise, the contact resistance goes up so the joint gets hot under load and can be a fire risk.
Soldered joints are OK as they are gastight, but you are not allowed to use solder-tinned wires in to screw terminals as the solder is soft & can continue to flow after the terminal has been tightened.
Jeremy
PS - My guess would be - as lurvbus intimated - that it's the different voltage that's the key to this - presumably the chance of sparking / arcing at a connection is a lot higher with 240v passing through it, so more effort is made to ensure a tight joint.
I have done a reasonable amount of electrical work, though certainly not on a professional scale. I have never seen a wire nut fail. However, if I use one in the bus I will generally put tape around the connector and wires just to be sure that vibration won't back it off. Again, I mention that I have yet to see a problem. Now, I am sure that others will have some contrary experiences.
Ok, so when you wire a light fixture in the ceiling. It comes with black white and green pr ground. How would you connect those three wires to your romex? Use a terminal? I'm not understanding how they do it in Europe . Jeremy, you have a pic?
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These?? (https://busconversionmagazine.com/forum/proxy.php?request=http%3A%2F%2Fimg.tapatalk.com%2Fd%2F13%2F07%2F15%2Futasy6ud.jpg&hash=3fc6bff678a45107392dff59511b1ee84cba9a81)
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Quote from: Scott Bennett on July 14, 2013, 07:55:28 PM
Ok, so when you wire a light fixture in the ceiling. It comes with black white and green pr ground. How would you connect those three wires to your romex? Use a terminal? I'm not understanding how they do it in Europe . Jeremy, you have a pic?
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...It comes with black white and green pr ground.I think this is the key difference because our fittings don't come with any wires attached, just terminals. Here are some pics:
(https://busconversionmagazine.com/forum/proxy.php?request=http%3A%2F%2Fwww.diy.com%2Fdiy%2Fjsp%2Fcontent%2Fknowledge%2Fimages%2Fhow_to%2Ffix_ceiling_light%2F1.gif%3Bdiybf03a07e37a34079&hash=d0c78ae59b16ab9b37ab8120c55cd9c8edb01da9)
(https://busconversionmagazine.com/forum/proxy.php?request=http%3A%2F%2Fwww.diy.com%2Fdiy%2Fjsp%2Fcontent%2Fknowledge%2Fimages%2Fhow_to%2Ffix_ceiling_light%2F2.gif%3Bdiyf517ca9342c393ac&hash=d86847f50c22d60780506ddbd767a783535e9d3e)
(https://busconversionmagazine.com/forum/proxy.php?request=http%3A%2F%2Fwww.diy.com%2Fdiy%2Fjsp%2Fcontent%2Fknowledge%2Fimages%2Fhow_to%2Ffix_ceiling_light%2F3.gif%3Bdiy735bbfa58d37c988&hash=37d3a9aae3df698019d50182d4ceb34d31f867a2)
So there you have three different types of circuit which all use the same type of standard light fitting, without the need for any 'extra' connections. But there may be other variations (as I said, for multiple switches etc) that do.
BTW, as you'll have gathered, our wiring colours are different as well
Jeremy
American junction boxes don't have terminal strips in them, at least I have never seen one with a terminal strip. I think wiring would probably be easier than wire nuts.
Doesn't the UK use very high amperage circuits and then each item has its own fuse or breaker? Here in the USA we use smaller circuits and depend on the breakers at the main box to trip if a circuit is overloaded.
Isn't most if not all of the power 3 phase in the UK it was in Germany
It's 3 phase in the same way that our power is 3 phase in North America, the distribution grid is 3 phase. Power distributed in residential type buildings is single phase (basically derived from one leg of the 3 phase, exactly the same as here), just at 220v instead of 120v. I don't know if high power appliances get split-phase 440 the way we get split phase 240. I have a mill motor that came in my Harrison mill that came from England that is 440 volt 3 phase, they ran it here on a step down transformer. Canadian industrial 3 phase is normally delivered at 600 volts, but you can get 208 volts as a special sometimes. The in-building power plant reduces it for normal single phase plugs and the machines mostly run on the 600 volts. When I got my Bridgeport it had a 600 volt 3 phase motor that I had rewound for 208 volts and I use a converter to start it, then it runs on split phase.
Brian
Quote from: luvrbus on July 15, 2013, 05:11:17 AM
Isn't most if not all of the power 3 phase in the UK it was in Germany
The power supply to the street is 440v three-phase, which is what industrial equipment used by businesses runs on. But houses only get half that - literally the houses on one side of the street take one leg of the supply, and those on the other side take the other leg - or so I understand it
Quote from: belfert on July 15, 2013, 04:55:27 AM
American junction boxes don't have terminal strips in them, at least I have never seen one with a terminal strip. I think wiring would probably be easier than wire nuts.
Doesn't the UK use very high amperage circuits and then each item has its own fuse or breaker? Here in the USA we use smaller circuits and depend on the breakers at the main box to trip if a circuit is overloaded.
I've no idea how amperages compare; here is a typical UK fuse box (or 'consumer unit', as they are called):
(https://busconversionmagazine.com/forum/proxy.php?request=http%3A%2F%2Fs7g3.scene7.com%2Fis%2Fimage%2Fae235%3F%24p%24%26amp%3Blayer%3D0%26amp%3Bsize%3D281%2C281%26amp%3Blayer%3D1%26amp%3Bsize%3D281%2C281%26amp%3Bsrc%3Dae235%2F72088_P&hash=d5f08d3cfed3ea9372824390df4c10d033514c09)
10-way, 16-module high integrity, insulated consumer unit with a smooth profile and flexible busbar. BS EN 60439-3.
100A Main Switch
2 x 63A RCDs
10 x MCBs (3 x 6A
2 X 16A
4 x 32A
1 x 40A)
10-Way (5+7+7 Way)
The two RCD (earth leakage trips) will be for the kitchen (and any outside supply) and the bathroom (ie. electric shower), because the law says you have to have RCDs wherever there is water in the vicinity to an electrical supply.
The two 16A breakers will be the lighting circuits (upstairs and downstairs), and the four 32A breakers will be for various ring mains (ie, outlet socket circuits). Not sure what the 40A breaker will be for - probably an immersion water heater supply.
http://www.screwfix.com/p/bg-10-way-high-integrity-populated-insulated-consumer-unit-dual-63a-rcd/72088# (http://www.screwfix.com/p/bg-10-way-high-integrity-populated-insulated-consumer-unit-dual-63a-rcd/72088#)
My bus incidentally has one of these (this exact model as it happens) - A three circuit consumer unit intended for sheds/garages/outbuildings:
(https://busconversionmagazine.com/forum/proxy.php?request=http%3A%2F%2Fs7g3.scene7.com%2Fis%2Fimage%2Fae235%3F%24p%24%26amp%3Blayer%3D0%26amp%3Bsize%3D281%2C281%26amp%3Blayer%3D1%26amp%3Bsize%3D281%2C281%26amp%3Bsrc%3Dae235%2F68849_P&hash=4e874ab736ae7044530ef2940e7071f22da7783e)
IP55. 5-module plastic, garage kit enclosure with a neutral cable and flexible busbar.
1 x 40A 30mA RCD
2 x MCBs (1 x 6A
1 x 32A)
http://www.screwfix.com/p/bg-garage-kit-enclosure-5-module-ip55-40a-rcd-dual-6a-32a-mcb/68849 (http://www.screwfix.com/p/bg-garage-kit-enclosure-5-module-ip55-40a-rcd-dual-6a-32a-mcb/68849)
Jeremy
Edit:- Brian was typing at the same time I was - what he says is correct. I've never heard of a house using the 440v supply for any 'domestic' equipment, but I'm sure it's doable in theory; certainly a friend of mine had a three-phase power supply installed at his home-based business to power the industrial sewing machines he uses. I also know that in certain fashionable circles (ie., mega-buck homes in London) it's de-rigur to have full restaurant-spec cookers etc in your home kitchen, which might well need a 3-phase supply
That's kinda what I thought here it not much of a problem starting and running a 3 phase motor on single phase but AC and refrigeration products are a little different refrigeration compressors that require the 208 3 phase there is no way to start those without a $$$$ converter on single phase and manufactures do not recommend it
I went through this not long ago when my son bought some commercial refrigerators from the UK
My experience with twist connectors (Wirenut is a brand name from Ideal), thousands of them, is to strip the wires about 1-1/2" then twist them tightly with pliers. Cut off the twisted wires about 1/2" beyond the insulation and install the wirenuts. They should also be tightened with pliers or a wirenut tool. Use only name brand products and Ideal is probably the best.
Please remove those images of European fuse panels...if our electrical code book people spot them, we'll all have to switch our panels to the same thing. ;)
Don't forget that in England a lot of electricity is retro-fit onto (not into) centuries old structure, the electrics run on the outside of the walls and that electrical panel may well be on the transom above a door... The plumbing is run on the walls outside, that sort of thing. And all products designed to be visible, look good and be safe. We hide our stuff inside walls, in basements, etc... They don't have inside of walls, or basements, sometimes.
Brian
Wow. So sorry to the OP for the thread drift but this is so interesting. I've been to a lot of countries but never paid much attention to how they do power as long as I had my converter. Fascinating. This matters to me because an older gent with a heart of gold wired our coach for
us but didn't twist the nuts tight enough in a couple of fixtures and the nuts smoked and melted. I replaced them and never had a problem but I'm not waiting for it to happen again.
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Back to the original issue: I think I figured out the issue with the breaker tripping. The voltage from the generator is dropping too low when the third A/C starts up causing the new Atwood A/C unit to blow the breaker.
The generator voltage unloaded is around 126 and with three A/C units it is about 112 or 113. Everyone I have talked to says I can go up to 130 unloaded. I just replaced the regulator so it should be working fine.
My generator voltage readings are similar to yours. Our frig gets a fault code about AC voltage being to high if the voltage goes above something like 125v. It can be a real balancing act.