RE: Changing 5th wheel from 30a to 50 a service ?s
where and how do you put that Killa watt in the system. it can't go on 50 or 30 amp input to RV.
bumpy
To measure voltage, you'd just plug it into any socket in the RV. It would tell you if the voltage was low and an autoformer would help.
RE: Changing 5th wheel from 30a to 50 a service ?s
Main problem is that during the heat of the summer while the a/c is running you have to be careful about what else you turn on.
A single AC should only draw 12-16 amps out of 30. No one has mentioned it, but it's possible the problem is voltage drop. As the voltage drops under load, current tends to increase for motor type loads. It might help to use a voltage booster (autoformer), which would reduce the current draw of the AC. If that didn't work, a power management system that drops off less critical loads as the full 30 amp limit is reached might help. Just buying a $20 Kill-A-Watt and tracking the power usage, voltage and current might identify the problem. I find I can run more 120V appliances from my gen, which gives me a full 120V, than when I plug in and only get 110V or less.
RE: How would you detect a NEUTRAL GROUND Reversal?
DryCamper11,
How could a pedestal that had a mis-wired neutral and ground be dangerous? One of your senarios was an open in the mis-wired ground, now the neutral, cable.
Follow the current. It goes from hot lead at service entrance to hot lead at pedestal. It goes into anything plugged into the pedestal - a light, the neighbor's RV, etc. It comes out to the bare ground wire (should be the insulated neutral). The bare ground is touching the metal pedestal. The ground wire to the service entrance is broken. Now you touch your pedestal and the adjacent pedestal (which has ground connected correctly) or any other ground. The current will try to flow from the metal pedestal through you to ground and back to the service entrance which has the neutral grounded to a large ground rod.
If no current is flowing, the ems acutated, how could you be electrocuted? I agree that if there's nothing else plugged into the faulty pedestal, there's no risk, but I can't be sure of that. Just plugging in a light or a tester or trying to figure out why there's no power could be enough to make the pedestal hot.
Until the circuits are completed in the MH,can current get to this lead. My ems would protect me under this situation. JM2¢...
This may be true - as long as you are certain that the neighbor isn't plugged into the same pedestal and you don't plug in anything. I say "may be" because I'm not certain how sensitive the EMS is to detection of an open neutral. When it tries to detect that condition, there will be some current flowing from hot to the EMS back to the miswired neutral/ground and possibly out of the box int earth ground and back to the service entrance. There won't be much, but the EMS could be confused if it sees that return path. A related problem is that the EMS itself is going to use current to make its tests, operate the relays, etc. That alone will make the pedestal hot. The RV will be protected, but the EMS will be trying to use current. It only takes 20-30 ma to kill you. Are you sure the EMS uses less than 20-30 ma?
RE: How would you detect a NEUTRAL GROUND Reversal?
Most campgrounds have multiple sub-panels from the main service feed. The ground buss at those sub-panel needs to be tied directly to earth as with any sub-panel and the neutral needs to run back to the main service panel before being tied to ground.
I agree.
I think a quick check would be to use a multimeter to measure the resistance between the metal box and the ground lug of a 50A receptacle - shoud be zero.
...
If the neutral and ground are reversed in the receptacle panel, the resistance will be higher due to the length of the neutral cabling.
While I agree with this, in a theoretical sense, trying to detect the difference between the two, in practice, may be very hard. The box may be painted or zinc coated, so you get some resistance trying to contact the box that you may not expect. There are connections at the socket, having contact resistance, so you will definitely get some resistance in all the measurements, not a perfect zero for any.
I'm not convinced you'd know if it was reversed, for certain. As an example - say the ground wire is connected to the neutral lug in the box and the neutral wire was connected to the ground lug. The ground wire is bare and may touch the pedestal a few inches from those connections, but it might not. It might not touch the metal components securely anywhere - it might just be lightly touching a rusty part of the box, or not touching anything until it reaches the adjacent pedestal.
RE: How would you detect a NEUTRAL GROUND Reversal?
The original post was dealing with shore power cable and a PI unit dropping out. I don't know how this got into the campground facility wiring.
Because it didn't say that in this thread. It asked how to detect ground/neutral swapping. Inspecting it or putting a clamp ammeter on the wires is how I'd do it.
RE: How would you detect a NEUTRAL GROUND Reversal?
Hence, this thread!
If you have a reversed neutral ground, I don't think you'd see any problems. The ground wire is bare and will likely contact metal components of the pedestal as it returns to the service entrance. That's the only problem. That's the same as having a ground to neutral connection at the pedestal. I had a ground to neutral connection at an incorrectly installed subpanel in my basement. I never noticed anything until I inspected it. I don't see how it could cause your symptoms. It's purely a safety issue AFAICT.
RE: How would you detect a NEUTRAL GROUND Reversal?
In DryCamper11 last post, the only way is to use an ems system the monitors an open neutral and turns off power to the MH thereby isolating the return path, hence no issue. JM2¢...
I don't think that having a pedestal next to my RV that could electrocute me is "no issue" even if my RV is perfectly safe from damage. I wasn't even thinking about the RV very much, just safety. Even without an EMS, an open neutral is no problem for my 30A RV - it just won't have power, whereas for the 50A RV, it will start blowing things into smoke clouds with an open neutral.
RE: Should you load test 6V deep cycle batteries?
You want to be careful when load testing a true deep cycle battery, they are not made for sudden high draw applications.
It's true that deep cycle batteries are not made for sudden high current draw applications, but I haven't heard that trying to draw lots of current will hurt them in any way. They just won't supply the high current the way an SLI battery with lots of thin plates will. It's sort of like comparing a sports car and a tank. The tank isn't made to accelerate fast, but it won't hurt it to stomp on the accelerator pedal. In fact, I tend to think of the SLI battery as being more likely to be injured with high draw. It tends to heat up and that may warp the SLI's thin plates and do more damage than will occur to the heavy thick plates in the DC. You just have less surface area in the DC to provide lots of current suddenly.
DC batteries are regularly used for electric cars and that's a pretty high current application.
RE: How would you detect a NEUTRAL GROUND Reversal?
Lets say that the pedestal is the main in your house. The neutral and ground are connected together in the box. If you touch the box you are touching the neutral, correct. So now you loose the neutral, if it is a 50 amp, things go up in smoke if it is a 30 amp things just don't work. The ground is still connected to ground and is doing its job. There are municipalities that require an RV pedestal to have its own ground rod and be nuet/ground bonded. As I said earlier the safety of the pedestal and the electrical supply might be compromised but the rv is OK as long as the bond exist.
I think we're talking about different situations. I'm worried about situations where the metal parts of the pedestal are connected to the wire providing return current to the service entrance (usually the neutral, but in this scenario, it's the ground wire). If that wire breaks and you are touching the metal parts, there is a hazard since you may form part of the return path as it tries to return via ground.
RE: Remote water pump control - latching relay?
Why not just use a wireless 12 volt remote controller. There are quite a few out there with a quick Google search....
I've never been happy with wireless controls. Running a wire is easy for me. I just need to find the right relay.
RE: Remote water pump control - latching relay?
you can add a LED Pilot light at each switch location using the same two wires. Here is a Manual and on page 2 read "How it works".
Have fun with your upgrade.
Thanks for the manual link. As I suspected, it uses a FET and a small control circuit. It probably works great, but if I can find one that's relatively inexpensive, I'll go with a ratcheting relay. I'm sure one of the relay manufacturers has one that will work. If I decide I want a light at each switch, I'll just have to run a third wire. I suspect I'll just leave the light at the main switch I have now.
RE: How would you detect a NEUTRAL GROUND Reversal?
If you can access the actual wires, a clamp on amp meter can be used to determine which is the neutral & which is the ground.
I agree, this is the most reliable method. However, it's not going to make the park owner happy for you to open up the pedestal.
On the issue of current in the coax - it's a common problem that doesn't necessarily mean there's a reversed neutral ground. The coax should normally be grounded upon entering a dwelling, but you still get AC on the ground. They sell ground breaker coax connectors to help control ground lops and prevent AC hum from getting into audio equipment from the coax.
RE: How would you detect a NEUTRAL GROUND Reversal?
I don't believe a GFCI within the RV will trip if there's a ground neutral reversal behind the pedestal. The GFC unit must be upstream of the reversal, not down stream.
Sal
OK- I'll say that a GFCI will trip with a ground neutral reversal, it can be tested without looking at the wiring, and a simple 3 light tester will *not* test for that, so a tester can be made with a GFCI outlet (if you want to test before connection), or you can simply turn on anything in the RV that is protected by a GFCI.
Reasoning for this- the ground would be carrying the current and the neutral will not, so there will be a huge imbalance between the hot and neutral, which is what trips a ground fault device.I agree with Sal. GFCI will only detect faults at the GFI or downstream and the fault, if it exists, is upstream of the GFI even if the GFI is in the pedastel. And the 3 light tester won't work either. I'm stumped as to how to detect it.
I disagree- the GFCI doesn't need to know where the fault is, as long as there is a current imbalance between the hot and neutral it will trip. If the ground is carrying the current, there will be an imbalance, no matter where the fault is. Think of it as being the same as an incorrectly installed GFCI- if you switched the ground and neutral on the inlet side of a GFCI, it would trip.
Sal is right. The GFCI measures current from the hot lead connected to it that is going out through the GFCI. It compares that current to the current coming back on the neutral, which is also connected to it. If the neutral and ground are switched between the service entrance and the pedestal, the currents the GFCI can see will match. The GFCI will still do its job of detecting leakage from a tool or RV to ground, but it won't detect the reversed ground and neutral connections leading to the GFCI.
RE: How would you detect a NEUTRAL GROUND Reversal?
I don't believe a GFCI within the RV will trip if there's a ground neutral reversal behind the pedestal. The GFC unit must be upstream of the reversal, not down stream.
I agree with Sal. It won't trip even if there's a GFCI in the pedestal with reversed neutral ground. The leak to ground has to be after the GFCI.
RE: How would you detect a NEUTRAL GROUND Reversal?
The reversal may not be seen as an electrical fault. The wire is undersized, but that's not a fault. How can it be a fault if you can't detect a reversal at the MH?
Sal
In my opinion, a properly grounded system is going to be the potential life saver IF and WHEN the FIRST FAULT comes along.
When the FIRST FAULT already exists as a NEUTRAL GROUND reversal it could be a lethal situation when that SECOND FAULT is introduced. IMO
I agree with Harvard. The first "fault" is that the return wire (what should be the neutral) is connected to ground at the pedestal. Touching the pedestal is the same as touching the neutral wire. That's a fault. If the return line breaks after the pedestal (the second fault), then the metal parts of the pedestal will be live. You'd have 120 volts across your body in series with anything plugged into the pedestal.
RE: Remote water pump control - latching relay?
Well I thought as long as you are pulling wire....
I looked for a wireless system to no avail :(
I appreciate the help - didn't mean to sound like I didn't :) It's just that at 12 volts you lose a lot of power running long power cables. It's a lot easier to run small wires than big ones. I'm still going to look around for a ratcheting type mechanically operated latching relay. I'm worried that the Intellitec unit is a solid state design. They tend to use power while off and I just prefer mechanical relays over electronic.
RE: Remote water pump control - latching relay?
Single pole double throw switches will do it.
My home kitchen lights have four switches to control..... just need to dig up a wire diagram.
To do it that way, I have to carry the 12 volt power all over the RV through long power leads. It will work better to have a short power lead to the relay and small low current control lead wires.
RE: Remote water pump control - latching relay?
Intellitec makes a latching water pump relay- it uses a single wire which is grounded to switch, making it easy to add remote switches.
Thanks, that looks like it would work. I wonder what the draw is when on and if it has any power draw when off. I found some ratcheting relays that used a positive pulse, but they drew power when off. They also needed a socket. That unit would mount more easily.
RE: Remote water pump control - latching relay?
Seems like more work than it's worth:H
I guess anything is possible with an RV, but I really wonder why you couldn't walk the 20' to turn it on/off if needed.
It would probably make more sense, to repair any leaks, rather than go to the effort of wiring the RV?
When the pump starts to leak at 2:30 AM, I'd rather reach over and switch it off than crawl across the wife to get to the other side. When my hands are covered in filth and my boots are muddy from fishing/cleaning fish and I need to wash up outside, if the pump was left off, I’d rather just turn it on than try to clean up enough to go inside and do it. AS to fixing it, there are times when I don't have a spare pump or the time to clean that bit of grit out of the one-way valve and I'd rather just wait until Monday instead of skip the fishing to work on the RV.
As to parts availability...I would think that you could probably get what you need at a place like Grainger's or most electrical outlets....maybe even HD or Lowe's?
I can find what I need in a ratcheting relay that uses a single direction pulse to go on/off, but there are lots of smart experienced people here. I thought I'd tap the expertise before going further.
