Hi mainah,
First off, I truly respect you and your background with electrical and campers. And with that, when you state an opinion on a topic, there is often a train of thought that comes across from experience over the years.
We have several of us here that come from different backgrounds and bring a lot of helpful and useful experience to our forum.
I have been trying thinking hard (racking one's brain for sure) on this trying to find out what I missed that you have such a definite train of thought that an overvolt of 220 into a camper is an immediate dead short to ground. I’m trying to understand what you see that I may have missed.
Quote:
Originally Posted by mainah
It will immediately trip a 220 breaker if so wireded because one lead would be a dead short to ground.
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Quote:
Originally Posted by mainah
30 amps at 240 across a load is going to smoke it either the camper breaker or the house breaker will trip unless it blows it to pieces.
Snip. .
If the converter is old and it does not blow up, for a little while you'll have a 24 volt DC system. Never seen a switching system survive overvoltage.
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You also keep bringing in the single point grounding comments, and that the white neutral is separate from earth ground in the camper. I 100% agree with you on this, the neutral is isolated from earth ground on purpose. Ground and neutral are only tied common at the main service entrance panel for shock/safety protection. I’m not sure why this keeps coming back into the discussion when you keep stating the camper breaker or the 220volt breaker will trip. Do you feel there is an actual neutral wire, working as a neutral wire that was crossed, in the camper when 220 volts is miss wired into it? If so, how is it there?
We only have 3 wires coming into the camper on the shoreline cord. When the incoming line is miss wired to 220 volts, from a double 220 breaker, that uses 2 of the shoreline wires. The actual black hot wire and the what was supposed to be white wire that is now miss wired as a hot leg. The 3rd wire is the earth ground. In this miss configured setup, there is no active AC neutral in the camper. There are 2 hot’s and the ground. At least from how I see it. If you disagree, please explain what I missed.
You also have a thought process that upon 220 v energization of the camper, there is an immediate dead short to ground. And now you seem to be saying a full 30 amps of 220 will smoke a converter. I agree that if a converter which normally only pulls approx. 1,000 watts on 120V at full load,( a 60 amp DC converter) if that load changed to create 6,600 watts (30 amps at 220V), odds are very favorable it’s smoked. And yes, that will trip the breaker.
I still do not understand your thought process on the instant dead short to ground. Where did it come from? Also how did the load change from 1,000 watts to 6,600 watts? I agree to touch 2 live 220V legs together will do it, but how does that happen? I do agree, switching mode power supplies are more sensitive to overvolt if there is no built-in protection. They have more sensitive electronics making DC power over a linear type.
I understand high voltage doing damage to sensitive electronics. Transistors don’t like it, nor do capacitors. From my background, over volts have usually burnt things open or melted them together. The device is for sure damaged, no doubt about it. On the one hand, doubling the voltage will cut the amps load in half. However, melted devices that still conduct can lower the resistance if they failed the right way which can increase the load if it gets big enough. But these electronics are on such small wire, when faced with 30 amps of 220V, the PC board current path should act a fuse and burn open I would think. So I’m still at a loss of where this instantaneous dead short to ground came in, or the actual load jumped to over 6,600 watts instantly? With some level of time being under high voltage, yes maybe, the load can burn itself that high if it did not burn up into an open circuit first.
I will add a sideline on the topic. I have seen the outcome of one camper from a miss wired RV outlet to 220V. The outcome was different then we are discussing here. And today, I believe I may have figured out why at least for part of it. There is learning from this, at least on my end. About 12 years ago, a buddy of mine wired a TT30R 30 amp RV outlet in his barn. He plugged the camper in, went inside and heard a bunch of clicking and buzzing from the power converter. Hearing this, he ran out and shut off the power. He then called to see if I could help him.
I have visions of what happened, but he lucked out in the end. He had an older Wadsworth 60 amp fuse panel with a 60 amp cartridge fused main pullout. The range pullout was unfused and not used. It had 4, Edison base screw in fuse holders. He had barn lights and some 120V outlets on 3 of the fuses, and he added a 120V 30 amp screw in fuse for his camper outlet. I checked the outlet wiring, and he that correct. I then pulled the cover off the fuse panel. Those older Wadsworth boxes also had 2 terminals above the Edison base fuses. By the wiring diagram on the panel cover, they appear to be for a water heater. He had the RV outlet black wire on the fuse base as it should be. But he goofed and put the white neutral on the hot water heater terminal instead of the AC neutral. Well, that terminal he picked is part of 220V water heater feed. Sure enough, he fed the camper 220V for what he said was between 30seconds to a minute by the time could get back and pull the main pullout.
I checked the power converter. There was a glass fuse on main PC board in line with the transformer and it was not blown. This converter appeared to like a linear converter, a year 2001/2002 camper. I could see the transformer, rectifier, what I believed was the voltage regulator, and the pull-up capacitors. It appeared to have survived the overvoltage by the lack of burnt smell or black soot on the PC board. It also had a Dometic microwave. Both were on when the 220 power surge came in. I corrected the neutral issue at the fuse panel, flipped all the breakers off in the camper, powered it up and checked the incoming voltage. He had 120V then. Turned the power converter circuit on, and the converter came up OK. Then the microwave. It came up OK too. I have no good explanation of how the microwave survived.
I told him to keep an eye on it, but be expecting in the future, you may have shorter life on the power converter or microwave. He was lucky that day and happy. In this case, 30 seconds to a minute did not kill the system. I do not recall what brand power converter he had or the sticker rating on the incoming line.
I did some more digging today, trying to sort out how his power converter may have survived. I have an old 2003 vintage power converter (made in the USA) I pulled out of my T310SR. Looking at the tag on it, it is a switching power converter and dual voltage rated. See here.
I’m not sure if he was dual voltage rated but or had over volt protection, it might have been, which is at least one reason his converter was not damaged.
Here is the same brand but a newer version in my older 2004 T2499. (made in China) It only lists 120 V.
I also looked up my Progressive Dynamic 9200 power converter. While it only lists 130V AC max input, it has this in the manual about protecting itself from an over and under, line voltage situation. The unit shuts down and will come back alive when the conditions go away. See here page bottom right on page 3. (another good reason to get a PD converter)
https://www.progressivedyn.com/wp-co...al-english.pdf
I looked at WFCO, IOTA, Booddocker, and they all state 130 VAC max and do mention any reference of line monitoring shutdown like the PD converter has. I do not know how those brands will fair in an overvoltage situation.
I looked up the Dometic microwave in our camper; it only lists 130 V Max.
It appears some converters may be able to handle a high voltage situation, how long is an unknown. I still have no idea how the microwave on my buddies camper survived. I would have thought it would have the hardest time.
One thing for sure we both agree on, 220 volts into a standard 120 V camper is a bad thing.
John
Linear Mode
