electrical problem

CharlesinGA wrote:


In the graphic above, replace the 10 ohm and 30 ohm resistors with something like a 1000 watt microwave, and a 300 watt heater element in the absorption fridge. If you have two exactly identical loads on opposing hots, they you won't see the effects of a open neutral, but since this is impossible, any imbalance of loads causes one side to be high and one to be low voltage.

At home, in an RV or anywhere, and open neutral is the biggest hazard you can encounter in electrical circuity, as far as damage to your appliances and devices.

Second to that would be surges, from lightning strikes or shorting of power company equipment.

Charles

Very nice example. Thanks

dougrainer wrote:

larry cad wrote:

dougrainer wrote:
Lets handle some misstatements here.
220 versus 120. Well, for RV's below 500K, this is a non issue. It allows smart alecks to tout their limited knowledge when they claim YES, there is 220(240) to the RV. Technically, yes. But the systems are built and separated that ONLY 120 volts is in the RV. ALL the claims of 220(240) do is make people think they have that when they do NOT. It just confuses them. They always tout the HI LINE RV's that have 220 dryers and such. Well. this forum is not about Hi line RV's, it is for the 99 percent that are under 500K. People that have million plus RV's do not read these forums and they certainly do not attempt to repair problems themselves. Doug

Sorry Doug, I have to disagree with you.



I am "IN" my RV. I am in the bedroom of my RV. My RV is not a "hi line", and no where near $500,000, and I fix my own RV. I am not a smart alec, and I DO know what I am talking about because I do electricity for a living, and I spent several years gaining a degree in electrical engineering just to back it up, so please don't tell me that there is no 240v in my RV and please don't confuse the issue more than it already is by making additional misstatements.

The real confusion happens when people don't understand the difference between 50 amp RV service and 30 amp RV service. However, the 240v that is in the RV can be a real problem is there is a loose neutral, for example.

Not trying to cause trouble, just trying to clear up an ongoing problem.

THIS IS WHAT I POSTED. NEVER said there was NOT 220/240. Doug
"YES, there is 220(240) to the RV. Technically, yes. But the systems are built and separated that ONLY 120 volts is in the RV"

Perhaps we should examine our phraseology and maybe it's nit-pickin, by "in", do you mean "inside", or do you mean "available", as in a 240v outlet? If you mean "available", you are correct, it is not readily available. It is, however, "in" the RV. Inside the breaker panel, as the photo shows. And it is somewhere in the power system that a loose neutral can cause havoc because the two separate 120v lines rely on the neutral to keep the 240v balanced. As has been pointed out, a loose neutral can cause a much higher voltage than 120v to be applied to the 120v load, resulting in damage to the device. The key point here is that IF there were NO 240v to begin with, there would be no damage possible. That it is not readily available to the RVer is not important. That it exists all the way from the power post, and into the RV breaker panel is enough to cause electrical damage if the neutral is not properly connected at some arbitrary point in the system.

(Doug, you know I respect you. I have mentioned your knowledge, ability and experience on this forum many times over the years)

In the graphic above, replace the 10 ohm and 30 ohm resistors with something like a 1000 watt microwave, and a 300 watt heater element in the absorption fridge. If you have two exactly identical loads on opposing hots, they you won't see the effects of a open neutral, but since this is impossible, any imbalance of loads causes one side to be high and one to be low voltage.

At home, in an RV or anywhere, and open neutral is the biggest hazard you can encounter in electrical circuity, as far as damage to your appliances and devices.

Second to that would be surges, from lightning strikes or shorting of power company equipment.

Charles

larry cad wrote:

wa8yxm wrote:

rgatijnet1 wrote:
In my house, the neutral and ground are tied/bonded together in the main electrical panel. In the RV, the neutral and ground are not tied together in the main panel.

This is not true.. When you plug into the park pedistal, they are bonded, your RV is considered a "Sub Panel" I know exactly where mine is bonded 7 sites west of me (where the main panel is).


However it is true that when you are not plugged into a properly wired outlet,, Yes, then they are not bonded. This often includes both Generator and inverter power.. They may or may not (usually not) be bonded. My inverter is bonded if inverting. Not if Generator is in use.

But the RV is a "Sub" panel off the park main, and it's the park main where the bonding happens.

You should re-read what the this person said.

Thank you for pointing this out, Yes I did mis-read his original post, Apologies (I thought he said "not Bonded" and "RV" not House and Bonded) He was quite correct.

Again thanks for catching it.

larry cad wrote:

dougrainer wrote:
Lets handle some misstatements here.
220 versus 120. Well, for RV's below 500K, this is a non issue. It allows smart alecks to tout their limited knowledge when they claim YES, there is 220(240) to the RV. Technically, yes. But the systems are built and separated that ONLY 120 volts is in the RV. ALL the claims of 220(240) do is make people think they have that when they do NOT. It just confuses them. They always tout the HI LINE RV's that have 220 dryers and such. Well. this forum is not about Hi line RV's, it is for the 99 percent that are under 500K. People that have million plus RV's do not read these forums and they certainly do not attempt to repair problems themselves. Doug

Sorry Doug, I have to disagree with you.



I am "IN" my RV. I am in the bedroom of my RV. My RV is not a "hi line", and no where near $500,000, and I fix my own RV. I am not a smart alec, and I DO know what I am talking about because I do electricity for a living, and I spent several years gaining a degree in electrical engineering just to back it up, so please don't tell me that there is no 240v in my RV and please don't confuse the issue more than it already is by making additional misstatements.

The real confusion happens when people don't understand the difference between 50 amp RV service and 30 amp RV service. However, the 240v that is in the RV can be a real problem is there is a loose neutral, for example.

Not trying to cause trouble, just trying to clear up an ongoing problem.

THIS IS WHAT I POSTED. NEVER said there was NOT 220/240. Doug
"YES, there is 220(240) to the RV. Technically, yes. But the systems are built and separated that ONLY 120 volts is in the RV"

DrewE wrote:

wa8yxm wrote:

However it is true that when you are not plugged into a properly wired outlet,, Yes, then they are not bonded. This often includes both Generator and inverter power.. They may or may not (usually not) be bonded. My inverter is bonded if inverting. Not if Generator is in use.

But the RV is a "Sub" panel off the park main, and it's the park main where the bonding happens.

For a built-in generator in an RV, neutral and (chassis) ground should be bonded together per the NEC, as I understand things. If it isn't, then the installation isn't quite right. On my motorhome. they are indeed bonded at the generator by having the ground and neutral leads from the generator connect to the same star-shaped connection doohicky on the generator chassis (which is also where the 12V chassis ground return line is connected).

On a (small) portable generator, neutral and ground are generally not bonded together, I suppose because sometimes these will be hooked up to a household electrical distribution system and having two neutral/ground bonds is to be avoided.

Exactly correct. Well said.

wa8yxm wrote:

However it is true that when you are not plugged into a properly wired outlet,, Yes, then they are not bonded. This often includes both Generator and inverter power.. They may or may not (usually not) be bonded. My inverter is bonded if inverting. Not if Generator is in use.

But the RV is a "Sub" panel off the park main, and it's the park main where the bonding happens.

For a built-in generator in an RV, neutral and (chassis) ground should be bonded together per the NEC, as I understand things. If it isn't, then the installation isn't quite right. On my motorhome. they are indeed bonded at the generator by having the ground and neutral leads from the generator connect to the same star-shaped connection doohicky on the generator chassis (which is also where the 12V chassis ground return line is connected).

On a (small) portable generator, neutral and ground are generally not bonded together, I suppose because sometimes these will be hooked up to a household electrical distribution system and having two neutral/ground bonds is to be avoided.

wa8yxm wrote:

rgatijnet1 wrote:
In my house, the neutral and ground are tied/bonded together in the main electrical panel. In the RV, the neutral and ground are not tied together in the main panel.

This is not true.. When you plug into the park pedistal, they are bonded, your RV is considered a "Sub Panel" I know exactly where mine is bonded 7 sites west of me (where the main panel is).


However it is true that when you are not plugged into a properly wired outlet,, Yes, then they are not bonded. This often includes both Generator and inverter power.. They may or may not (usually not) be bonded. My inverter is bonded if inverting. Not if Generator is in use.

But the RV is a "Sub" panel off the park main, and it's the park main where the bonding happens.

You should re-read what the this person said. You are telling him what he said is not true and in doing so, you have added to his confusion. He referred to the panel in his RV as his "main" panel. And that is true, for his RV. However, as far as National Electrical Code is concerned, his "main" panel is actually a "sub-panel" and it is NOT bonded in the panel. What you say is correct, in that the neutral and the ground in the RV are bonded together in the main panel of the campground.

dougrainer wrote:
Lets handle some misstatements here.
220 versus 120. Well, for RV's below 500K, this is a non issue. It allows smart alecks to tout their limited knowledge when they claim YES, there is 220(240) to the RV. Technically, yes. But the systems are built and separated that ONLY 120 volts is in the RV. ALL the claims of 220(240) do is make people think they have that when they do NOT. It just confuses them. They always tout the HI LINE RV's that have 220 dryers and such. Well. this forum is not about Hi line RV's, it is for the 99 percent that are under 500K. People that have million plus RV's do not read these forums and they certainly do not attempt to repair problems themselves. Doug

Sorry Doug, I have to disagree with you.



I am "IN" my RV. I am in the bedroom of my RV. My RV is not a "hi line", and no where near $500,000, and I fix my own RV. I am not a smart alec, and I DO know what I am talking about because I do electricity for a living, and I spent several years gaining a degree in electrical engineering just to back it up, so please don't tell me that there is no 240v in my RV and please don't confuse the issue more than it already is by making additional misstatements.

The real confusion happens when people don't understand the difference between 50 amp RV service and 30 amp RV service. However, the 240v that is in the RV can be a real problem is there is a loose neutral, for example.

Not trying to cause trouble, just trying to clear up an ongoing problem.

rgatijnet1 wrote:
In my house, the neutral and ground are tied/bonded together in the main electrical panel. In the RV, the neutral and ground are not tied together in the main panel.

This is not true.. When you plug into the park pedistal, they are bonded, your RV is considered a "Sub Panel" I know exactly where mine is bonded 7 sites west of me (where the main panel is).


However it is true that when you are not plugged into a properly wired outlet,, Yes, then they are not bonded. This often includes both Generator and inverter power.. They may or may not (usually not) be bonded. My inverter is bonded if inverting. Not if Generator is in use.

But the RV is a "Sub" panel off the park main, and it's the park main where the bonding happens.