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Re: Voltage Drop - NOT Park Problem
wnjj wrote: ThruTraffic wrote: wnjj wrote: I think this was mentioned earlier but you need to put a decent load in the RV then measure the voltage at every possible place you can between the source and load. You’ve said the voltage is good at the pedestal and bad at the load. This means there is a resistive connection somewhere. While under load, measure the output side of the breaker the load is connected to in the RV panel. Then measure another one to eliminate the breaker and wiring to the load. Next move upstream to the feeder line, transfer switch, etc. The problem will be between the last “good” voltage and first “bad” one. 25 amps good enough? Note my last big post. There's nothing left to test; it's all new. Maybe I'm missing something but I saw a post with various voltage drops measured with increasing loads turned on but not one where you measured multiple places along the same circuit. Your last big post talks about replacing a bunch of stuff. Neither of those addresses my suggestion. When you have a voltage drop between two end points, there has to be an explanation. If it's simply due to wire size/length it will continuously decrease along the way and as you say it will be normal. If what you are experiencing is abnormal, there must be someplace causing the drop. Rather than guessing, you should measure the voltage along every specific place you can access between the supply and the load. You're also a bit all over the place with changing shore power cords and pulling the meter when as you said, the same happens on the generator. So the problem either persists inside your RV, or it's not actually a problem at all and is normal. Does anyone actually think I've not been measuring voltage during every test or component replacement? NEC: The National Electrical Code contains six Fine Print Notes to alert the Code user that equipment can have improved efficiency of operation if conductor voltage drop is taken into consideration. 1. Branch Circuits – This FPN recommends that branch circuit conductors be sized to prevent a maximum voltage drop of 3%. The maximum total voltage drop for a combination of both branch circuit and feeder should not exceed 5%. [210-19(a) FPN No. 4], Figure 2. 2. Feeders – This FPN recommends that feeder conductors be sized to prevent a maximum voltage drop of 3%. The maximum total voltage drop for a combination of both branch circuit and feeder should not exceed 5%. [215-2(d) FPN No. 2], Figure 2. I can measure a normal voltage of 121v to to a low of 108v under a less than 25 amp load. Using 5% of 121 volts results in an acceptable loss of 6.05v or 121 down to 114.5. Do you think 108 is normal or acceptable? My old a/c compressor had a locked rotor current of 51 amps. Under the conditions I've described it's no wonder the the compressor died when attempting to start with a voltage that low. No way can a start capacitor overcome that for very long. So let me ask all the "that's normal" believers who own 30amp rigs: What happens to the voltage in your RV when you throw a water heater and a microwave and a toaster at it. Do YOU loose ~10% of normal voltage?1.1KViews0likes0CommentsRe: Voltage Drop - NOT Park Problem
time2roll wrote: wnjj wrote: I think this was mentioned earlier but you need to put a decent load in the RV then measure the voltage at every possible place you can between the source and load. You’ve said the voltage is good at the pedestal and bad at the load. This means there is a resistive connection somewhere. While under load, measure the output side of the breaker the load is connected to in the RV panel. Then measure another one to eliminate the breaker and wiring to the load. Next move upstream to the feeder line, transfer switch, etc. The problem will be between the last “good” voltage and first “bad” one. Yes keep poking around until most of the voltage drop is found. Should not take more than a few minutes once there is access. Tightening a connector is not proof that it is functioning... need to measure. Hard to tell what the error codes are saying without the owner's manual. See first and last big post. Residential type 120/240v electrical systems don't give error codes.1.1KViews0likes0CommentsRe: Voltage Drop - NOT Park Problem
Dusty R wrote: Maybe try a heat sensor, and check the entire path that the current will flow. Again, last big post; entire wire pathway has been replaced, and rerouted to shorten it which all by itself should help abate any attenuation issues.1.1KViews0likes0CommentsRe: Voltage Drop - NOT Park Problem
wnjj wrote: I think this was mentioned earlier but you need to put a decent load in the RV then measure the voltage at every possible place you can between the source and load. You’ve said the voltage is good at the pedestal and bad at the load. This means there is a resistive connection somewhere. While under load, measure the output side of the breaker the load is connected to in the RV panel. Then measure another one to eliminate the breaker and wiring to the load. Next move upstream to the feeder line, transfer switch, etc. The problem will be between the last “good” voltage and first “bad” one. 25 amps good enough? Note my last big post. There's nothing left to test; it's all new.1.1KViews0likes0CommentsRe: Voltage Drop - NOT Park Problem
bob_nestor wrote: I once had a similar problem but I see you stated in your original post that: "- Checked connections at transfer switch, socket for shore power, junction where old EMS used to be, mains in RV breaker panel. Checked neutrals, grounds and feeds. All tight." ... so I'm not sure if this helps any, but... The source of my problem was in the main RV breaker panel. Even though all the connections were tight I discovered that someone (at the factory) had cross threaded the screw holding the neutral line in the box. (Things worked for for a few years, then I had power issues.) The screw was tight but hadn't been holding the wire very well and over time the connection degraded with a patina build-up similar to what happens in the contacts in the transfer switch. I had to remove and replace the small bus bar the neutral was attached to and that fixed my problem. I pulled a new feed from the t-switch to the breaker panel so no patina on the main feed. I didn't replace the neutral buss but I did re-seat all the neutral and ground terminals and even bonded the neutral and ground buses and that made no difference. (bonding removed now). The only thing I have not replaced is the breaker panel. :-) I really can't see how that would fix anything but at this point I'm not discounting divine interference. LOL363Views0likes0CommentsRe: Voltage Drop - NOT Park Problem
Here's an update: - Problem persists. - Moved RV to different site feed (site is where I park my RV most of the year fed off a 200a 240 v service in a 50x50' shop. RV is the ONLY place a voltage drop appears. I have a 100a feeder to an RV pedestal outside for summer and an RV plug inside for winter that is ~3' of #10 wire from the main 200a panelboard. - Replaced the shore power cord with a new one 25 feet shorter. - Replaced transfer switch. - Replaced the shore plug to t-switch feeder. - Replaced the t-switch to main panel feeder. - Old EMS junction no longer in circuit. - Took inverter off line; disconnected runs and jumpered the two breakers it used). - Disconnected the charger. - Replaced the main breaker. - Released and retightened all breaker panel terminals. - I even get the same voltage loss with the neutral bonded to the ground in the breaker panel. FYI I spent 20 years as a lineman and a residential/commercial electrician so I have a bit of a clue what I'm doing. I'm not above mistakes and errors in this field but they're pretty rare. Every time I made a change I retested for the problem and each time the results were the same; unacceptable voltage loss. So, I've pretty much rewired the RV so I'm going to have the power company come cut the seal and pull the meter so I can tighten the main lugs on the service and main panel. I can't find anything currently that points to that being a problem but aluminum wire/lug connections are known to loose up over time but not normally in the short time this service was installed. If the panel lug task doesn't resolve it I'll have the power company check the transformer and underground lateral for problems. They just a month ago replaced the main primary through here and I've noticed since they energized it there is a 4 to 5 voltage variation under no load throughout the day. That said I've seen no evidence it's a building or service issue. I have a friend who stays a couple of times a year. He saw no issues plugged into the same pedestal I was although in hindsight his rig is 50A, 240 volt. It's possible he would not see a loss but that would be a weird set of wiring coincidences I think.364Views0likes0CommentsRe: Voltage Drop - NOT Park Problem
valhalla360 wrote: ThruTraffic wrote: From initial post : Problem persists when disconnected from shore power and generator running. Main indicator this is an RV wiring problem not shore power delivery system." If I took the rig to Walmart's parking lot and ran it off the generator and still had the same problems would one believe it was shore power? Did the generator handle the air/con in the past without problem? Otherwise, tracing the voltage from the entry point of the RV to the air/con is the logical process to find the issue. Another quick verification is can a neighbor plug into your pedestal and verify their air/con comes on without problem? Yes Done Done Please note people: This is NOT an A/C problem. A/C circuit is disconnected. A.C was just an example VICTIM.363Views0likes0CommentsRe: Voltage Drop - NOT Park Problem
marty1300 wrote: I had a 120 volt issue a while back. On shore power all was well. On generator is where the issue was. From our generator to where the transfer is made (manual transfer). There was a junction about 3 feet away where the stranded wire from generator was spliced into the solid wire that would go to transfer plug in back compartment. Look in a compartment near generator you may have same scenario. My wires had come apart an eventually burned. No junction. Straight shot from shore plug to transfer switch (which I replaced.)363Views0likes0Comments
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