Southwire Surge Guard 34951

[hillbilly3]

Has anybody had issues with these tripping out randomly? My son in law's will trip out on high neutral amps (644). The first park said they have had issues from several people that used them with their pedestals. They had them checked out, and could not find any problems. He stayed at different park this weekend, and it tripped out again. The 30 amp version I gave him works fine ( until he runs the A/C, coffee pot and water heater, I know what his issue is there! LOL!). I think it is actually unbalanced voltage causing the tripping, because the 50 amp rigs tend to have a heavier load on one leg, then that is compounded by every other 50 amp rv on that feeder. The only thing on the other leg is a new A/C unit over the bedroom.

[twinboat]

In a standard 120/240 volt 50 amp service, neutral only carries the difference between each leg.

If L1 is at 40 amps and L2 is at 10 amps the neutral carries 30 amps.

Even If one leg is at 50 amps, with nothing on the other leg, its still should only be 50 amps on the neutral, never more.

[hillbilly3]

Originally Posted by twinboat

In a standard 120/240 volt 50 amp service, neutral only carries the difference between each leg.

If L1 is at 40 amps and L2 is at 10 amps the neutral carries 30 amps.

Even If one leg is at 50 amps, with nothing on the other leg, its still should only be 50 amps on the neutral, never more.

Correct, but because the feeder running all of the pedestals has a much greater load on one leg than the other, it causes the voltage to be lower due to the length of the wire from the main panel or meter on that leg, so the surgeguard see's it as out of balance. Don't know why it displays the neutral amperage in the hundred's unless it's calculating startup current, but according to their troubleshooting guide, the imbalance is what causes it to trip out. If campgrounds alternated the phasing at every other pedastal, it would probably cure the problem, along with giving better power quality.

[Persistent]

Hillbilly,


I don't know what the number you reported means. It may be an error code. I think it does not mean 600 amps. At least two circuit breakers in the 50 amp pedestal and RV would trip instantly.


Multiple heavy users on the campground grid can lower both L1 and L2 voltage. That increases the current drawn by air conditioning motors and refrigerator motors if you have one. As posted above it is dependent on the difference between L1 and L2 current.



Look in the manual for the surge protector to find out what the error code means. It may be reporting an issue with grounding or excess voltage on the neutral wire. Excess voltage on the neutral may be caused by corroded or loose connections somewhere in the grid wiring. Check voltage between ground and neutral to determine if there is excess voltage on the neutral.


It would be amplified by heavy grid use depending on where the defect is located. Changing sites may or may not solve the problem depending on where the defect is.


I wish you good luck and happy trails ahead!

[Ljwt330]

Just a note to add.

I looked at the owner's manuals for both the 50 amp and 30 amp versions of the protector. The 30 amp version does not have high neutral trip protection, so that's probably why your son has no issue when using the borrowed 30 amp unit.

The 50 amp trip when the neutral exceeds 130% of specified current. I suspect, as others, the "644" on the display is actually "65A", which would be the amp overage measurement.

I agree that the issue is likely low voltage at the pedestal from high demand in the park.

[hillbilly3]

Originally Posted by Persistent

Hillbilly,


I don't know what the number you reported means. It may be an error code. I think it does not mean 600 amps. At least two circuit breakers in the 50 amp pedestal and RV would trip instantly.


Multiple heavy users on the campground grid can lower both L1 and L2 voltage. That increases the current drawn by air conditioning motors and refrigerator motors if you have one. As posted above it is dependent on the difference between L1 and L2 current.



Look in the manual for the surge protector to find out what the error code means. It may be reporting an issue with grounding or excess voltage on the neutral wire. Excess voltage on the neutral may be caused by corroded or loose connections somewhere in the grid wiring. Check voltage between ground and neutral to determine if there is excess voltage on the neutral.


It would be amplified by heavy grid use depending on where the defect is located. Changing sites may or may not solve the problem depending on where the defect is.


I wish you good luck and happy trails ahead!

Actually you can have 600 amps without tripping the breaker, most breakers are designed with inverse time delay, in otherwords, the higher the current rise, the shorter the delay to trip. Apparently the Surgeguard is dropping the load faster than the breaker. Take motor loads, start up can be as much as 10 times or more as running current, but it's for such a short duration, a properly sized breaker does not trip. The problem with RV's, is they are inherently imbalanced, the normal loads are mostly on line one, while additional loads such as a second air conditioner is on line two. With everything running, you may have 30+ amps on line one, while line two, may only be 12-15 amps. Multiply this imbalance by 10 or 20 sites, line one's voltage will be lower than line two due to voltage drop.

[Persistent]

Your surge protector will never see more than your own unit is conducting. Current from other units does not flow through the surge protector. That includes the neutral.
644 amps would be treated as a dead short by the pedestal breaker, the RV main breaker, and the surge protector. Breakers would trip instantly.
Two air conditioners and a residential refrigerator all starting on the same leg of a 50 amp system could cause 64 amps in the neutral. But it would also cause 64 amps in the leg. 50 amp breakers would carry 64 amps for a brief period. I don't know what the surge protector is designed to do.

[Persistent]

I just thought of another scenario that could cause 64 amps in the neutral without tripping breakers.


If both hot legs in the pedestal are wired to the same hot side of the grid, each leg can carry 50 amps. In this case the neutral may be required to carry up to 100 amps.



So two air conditioners, one on each RV leg, plus one residential refrig, plus battery charger, plus electric water heater all distributed over two RV legs would all flow through the neutral wire.


Good catch for the surge protector.


I wish you good luck and happy trails ahead!

[hillbilly3]

Originally Posted by Persistent

Your surge protector will never see more than your own unit is conducting. Current from other units does not flow through the surge protector. That includes the neutral.
644 amps would be treated as a dead short by the pedestal breaker, the RV main breaker, and the surge protector. Breakers would trip instantly.
Two air conditioners and a residential refrigerator all starting on the same leg of a 50 amp system could cause 64 amps in the neutral. But it would also cause 64 amps in the leg. 50 amp breakers would carry 64 amps for a brief period. I don't know what the surge protector is designed to do.

Don't think I said anything about current from other units flowing through his surge protector, already checked voltage between legs, not the same leg..........but current on a short circuit can be as high as 10,000 amps or more depending on transformer size, breaker or fuse clearing time, wire length and size, utility voltage and other factors, I know, I am a master electrician licensed in four states.

[hillbilly3]

Looks like it is the voltage imbalance issue, we are at a state park in South Carolina that is not loop wired, pedastals are spidered from a main distribution panel, so voltage drop from unbalanced loop is not an issue. So far, he has no tripping.