RV park electrical loads

[Smart $]

... To me that suggests it is something other than the peak load that is tripping the breaker.

Consider the seasonal demand may be higher than Code-calculated demand. The percentages in Table 551.73(A) are the minimum allowable demand factors. The real-world demand may be higher, as it easily may have increased through the years.

 

[iwire]

Consider the seasonal demand may be higher than Code-calculated demand. The percentage in Table 551.73(A) is the minimum allowable demand factors. The real-world demand may be higher.

Of it 'may be' higher. We can say that about any NEC demand table. There is no way that any of of us could argue otherwise.

That said can anyone provide actual evidence, not anecdotal evidence that NEC minimum RV feeders are tripping due to overloads?

 

[kwired]

Of it 'may be' higher. We can say that about any NEC demand table. There is no way that any of of us could argue otherwise.

That said can anyone provide actual evidence, not anecdotal evidence that NEC minimum RV feeders are tripping due to overloads?

I thought it was already mentioned but here it is again, the informational note following 551.73(C)

Informational Note: These demand factors may be inadequate in areas of extreme hot or cold temperature with loaded circuits for heating or air conditioning.

Then throw in the fact OP said they are mostly if not all 30 amp sites, there is likely some RV's with 50 amp supply cord using a 30 to 50 amp adapter, so they naturally can load the 30 amp receptacle more then a RV with only a 30 amp supply cord throwing your demand factor off.

 

[iwire]

I thought it was already mentioned but here it is again, the informational note following 551.73(C)

That does not in anyway answer the question of mine that you quoted.

Then throw in the fact OP said they are mostly if not all 30 amp sites, there is likely some RV's with 50 amp supply cord using a 30 to 50 amp adapter, so they naturally can load the 30 amp receptacle more then a RV with only a 30 amp supply cord throwing your demand factor off.

So now you are trying to prove the calculation is wrong or undersized because people violate the rules?


The park has been around 40 years, unless this tripping has been a problem from the start I personly doubt that overloading is the issue.

There is so many other things it could be with 40 year old outdoor equipment, some of them you yourself have mentioned.

If this was my problem to solve I would put a recording meter on the feeder, of course that is easy to say when you have easy access to one.

 

[iwire]

A note about the note.

Informational Note: These demand factors may be inadequate in areas of extreme hot or cold temperature with loaded circuits for heating or air conditioning.

As a moderator I can see the area the OP lives, I do not know if they want to share that info so I will not.

What I will say is the area is a moderate one, more northern than southern.

 

[kwired]

That does not in anyway answer the question of mine that you quoted.



So now you are trying to prove the calculation is wrong or undersized because people violate the rules?


The park has been around 40 years, unless this tripping has been a problem from the start I personly doubt that overloading is the issue.

There is so many other things it could be with 40 year old outdoor equipment, some of them you yourself have mentioned.

If this was my problem to solve I would put a recording meter on the feeder, of course that is easy to say when you have easy access to one.

And 40 years ago there wouldn't have been as many RV's with 50 amp supply cords pulling in there and using a 30 to 50 amp adapter. If you just walk around while the site is in heavy use and observe that there is a lot of those in use - you probably have a good idea already that it is highly loaded.

 

[iwire]

And 40 years ago there wouldn't have been as many RV's with 50 amp supply cords pulling in there and using a 30 to 50 amp adapter. If you just walk around while the site is in heavy use and observe that there is a lot of those in use - you probably have a good idea already that it is highly loaded.

So you are still going with 'people will do stupid things' and we need to design for that.

 

[kwired]

So you are still going with 'people will do stupid things' and we need to design for that.

Not exactly, just pointing out the load needs have changed over the years. Probably time to install more 50 amp receptacles at the sites - then the load calculation will increase.

 

[growler]

And again we have no measurements of the actul load being drawn so in my own opinion we cannot tell why these breakers are tripping.

I do agree and think that someone should do an actual measurement of current draw. This would support the need for more power.

But I can easily see where 14 RVs may draw over 100 amps for a long enough time to trip a breaker. People have everything from microwaves to coffee makers in there.

 

[102 Inspector]

As indicated by the moderator, I am located in northern Indiana. The campground is seasonal so currently it is shut down for the winter time. The access road to get to the campground is tight, so they do limited the size of camper. This normally limits them to 30 amp hook-ups. I agree that the feeders need to be monitored to try to determine what is causing the trip. I will contact the POCO and see if they can data log it next spring when they open up again.
Would it do any good to meg to feeders during the off season to check for any bleed off due to damage to the underground? As it was stated, a bad report of power availability can really hurt the campground. It is beautiful and located around a lake setting inside the city limits. Would hate to deter people from using it. Thanks for all the comments. I will be talking to the park board shortly with ideas.

 

[mgookin]

That place is 40 years old. Have you gone around and tightened all the lugs and checked connections on everything?

 

[kwired]

That place is 40 years old. Have you gone around and tightened all the lugs and checked connections on everything?

And take readings while it is in use. Also take IR scans of main breaker/main lug temp while in use. If current is lower then trip level but high temp/ you might just need to change the main breaker.

During off season you could do some testing just by plugging in some portable 1000-1500 watt heaters and see if they have any thermal impact at the main. If you can get at least a 7.5 or 10 kw load on the main, if there is a problem that is probably enough load to make it show some symptoms of weak connections.

 

[cpinetree]

And take readings while it is in use. Also take IR scans of main breaker/main lug temp while in use. If current is lower then trip level but high temp/ you might just need to change the main breaker.

During off season you could do some testing just by plugging in some portable 1000-1500 watt heaters and see if they have any thermal impact at the main. If you can get at least a 7.5 or 10 kw load on the main, if there is a problem that is probably enough load to make it show some symptoms of weak connections.

see bold above.
That is probably the easiest way to simulate real world use.

You could also Megger everything and then torque all connections, and redo the heater test.

 

[mopowr steve]

If they only have a 30 amp receptacle at each site - you are not ordinarily going to run double/triple AC's without tripping the 30 amp breaker for that individual site. I suppose you may be able to plug your 50 amp to 30 amp cheater in and possibly run two AC's but will have little or no capacity for anything else. Then on top of that if you have a 20 amp receptacle at the site as well there could be additional load running on that.


Another thing to consider is load balancing - those 30 amp receptacles are 120 volt - Get too many on one line and not so many on the other line and you may trip the main - load calculations in NEC are typically just VA values and you need to spread that around on multiwire systems or go with a larger system if you are going to have an imbalance.

Yeh, when we tie the feeders into the pedestals I will flip/flop the phases at each one in an effort to keep the loads balanced (basing that on the internal connection of the 30 amp recept most commonly used)

 

[ptonsparky]

Megging the feeders certainly won't hurt. I have megged older direct bury rubber covered CU feeders that fail the insulation test without ever being able to locate a fault. My SEWAG is the whole feeder just leaks. AL will deteriorate rather quickly when the insulation is compromised, CU generally just keeps on working. Direct Bury. FOP testing of the feeder breakers should be high on the list as you are load testing. (that may have been mentioned already.