Max VD for 30 amp RV

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AC\DC

Senior Member
Location
Florence,Oregon,Lane
Occupation
EC
I have a feeder off the outdoor panel to 2- 30 amp pedestals. The farthest one if I run number #8 makes my total vd back to meter total of %6.38VD
if I run #6 %5.8VD. I know combined with Feeder and Branch should not be more than %5.
at 120volt with 6.38 I have a lose of 7.65volts so I ll be at 112.35 volts.
I am trying to find if the RV has a tolerance of +/- 10% like most equipment I have dealt with.


I have to do plan review with the county since I " touched the conductor". They told me there looking for VD issue. Though I don't know how they can enforce them unless the RV has a tighter tolerance.
No local Amendments that I am aware of.


Any help would be appreciated.
 
AC\DC said:
I have a feeder off the outdoor panel to 2- 30 amp pedestals. The farthest one if I run number #8 makes my total vd back to meter total of %6.38VD
if I run #6 %5.8VD. I know combined with Feeder and Branch should not be more than %5.
at 120volt with 6.38 I have a lose of 7.65volts so I ll be at 112.35 volts.
I am trying to find if the RV has a tolerance of +/- 10% like most equipment I have dealt with.


I have to do plan review with the county since I " touched the conductor". They told me there looking for VD issue. Though I don't know how they can enforce them unless the RV has a tighter tolerance.
No local Amendments that I am aware of.


Any help would be appreciated.
Click to expand...
Voltage drop isn't
enforceable unless they've changed it.
 
Inspector said that was one of the things they will look at.
Also don't want the client to be unhappy, so want the rv to work properly. I don't think they will ever run at max since we don't use AC in my area.
What voltage range would be good for you guys?
Thank you for the reply.
 
A lot of RV’ers use surge protection that has voltage range protection too. If the voltage gets too low, or two high, they will disconnect the RV. I have one on mine, but don’t remember what the drop out voltage was. Don’t forget that some have the choice of gas or electric water heating, and if A/C is not used that much, then heat likely will. A lot of RV’ers use portable electric heaters instead of the noisy gas furnaces, so keep that in mind also.
 
AC\DC said:
Inspector said that was one of the things they will look at.
Also don't want the client to be unhappy, so want the rv to work properly. I don't think they will ever run at max since we don't use AC in my area.
What voltage range would be good for you guys?
Thank you for the reply.
Click to expand...
That it a key to how much VD you might expect, as it is going to vary with actual load.

I would also think much RV equipment is designed to tolerate some VD, as it is probably a common issue encountered. Think how many adapters there are to run 30 amp and even 50 amp units from 5-15/5-20 receptacles, how many end up with some extension cord in the run, etc. Then how many get run from a generator, inverter, etc. where voltage maybe gets drawn down easily when loaded much.
 
The spot in question. Only has 1/2 pipe going to it for about 120’ trying to get by with #10 so I don’t have to dig it. But that voltage drop is like %5. Lol. So was trying to save on wire since I am going to probably dig a new tench.
I feel confident that the #8 will be fine.
Thank you
First RV park I am working on, will definitely approach this differently next time. Breaking even right now lol.
 
qcroanoke said:
Voltage drop isn't
enforceable unless they've changed it.
Click to expand...
Voltage drop is in the Oregon code for quite a while now:
Oregon Energy code
90.1-2019
Section 8 – 8.4.1
Voltage Drop

Two types of conductors
• Feeder conductors
– Connect service equipment to the branch circuit breaker panels
• Branch circuit conductors
– Run from the final circuit breaker to the outlet or load
Feeder conductors and branch circuits combined to be sized
for a maximum of 5% voltage drop total

State of Oregon: Energy in Oregon - Energy Code & the Built Environment

www.oregon.gov www.oregon.gov
Click to expand...
 
Seems like ASHRAE Standard 90.1-2019 only applies to Buildings, and if they say a RV pedestal on a post is Constructed. It still does not Support or shelter any use or occupancy.
I'll see if I can worm my way around.

Thanks Tortuga, so much stuff lol, I should just stick to re-wiring kitchens lol.
 
AC\DC said:
Seems like ASHRAE Standard 90.1-2019 only applies to Buildings
Click to expand...
Good catch its not a building.
Yeah that is the code equivalent of a land mine,I made a very expensive mistake missing that. . And I hopefully will never step on that one again.
It usually only comes up on commercial / industrial work, but technically I think it applies to all buildings, even residential.
 
Well you scared the $&@“ out of me so I got my weaseling little mind going.
Once again thank you for that. I am going to have to never forget this.
I did notice 90.2 applied to residents, but it seems Oregon did not adopts from my short reading.

if you don’t mind me asking how easy is plan review I have never done that yet. County inspector just told me to make a line diagram of the layout and they will review.
 
tortuga said:
Voltage drop is in the Oregon code for quite a while now:
Click to expand...
So what it the load amount you base the VD on in OP's case?

Looks to me like maybe you use load calculations in 551 for the base load? A single site with a 30 amp receptacle needs to have 3600 VA capacity, but there are demand factors you can apply to feeders and service for multiple sites, that can make a huge difference in VD if you go off full 3600 VA on many sites vs using whatever demand factor is listed for the number of sites you have. 10-12 sites the demand factor is 50%.
 
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