RV pedestals and the Tap Rule

[RD35]

I'm designing my first RV Park. The pedestals my customer wants are offered by more than one manufacturer and are very similar. They have a 2P50A, a 1P30A, and a 1P20A breaker with one receptacle each. Very common set-up. The breakers inside the pedestal are fed from a single phase 240V, 125A panel bus. The bus is fed by #1 copper tap conductors that are, in turn, fed by a set of lugs which also have double 6-350 barrels on each lug for the purpose of loop or daisy-chain feeders. From the data I have found I can both size and protect the feeders at an amperage up over 200A. The pedestal breaker bus is lug only (no MCB). So my question has to do with protecting that 125A bus. Is that bus considered protected so long as the total ampacity of the OCP on either bus bar does not exceed 125A? Is there a code section (tap rule maybe) that addresses this type of issue directly? (If so, I cannot seem to locate it)
Thanks

 

[ptonsparky]

Try 240.21(5)

 

[hillbilly1]

The pedastal is probably treated by the manufacture as less than 6 disconnects, so each breaker is a main. The total of the mains are less than the rating of the buss. I would think the manufacture would state the maximum ocp on the input, unless each pedastal is service rated.

 

[electrofelon]

Not sure if these are panel boards or not, but If so 408.36 would require the bus be protected at it's rating, and there is no exception for "sum of multiple breakers" (unless it's a service panel board).

Regarding the conductors themselves, 240.21(5) requires the outside tap terminate on a single OCPD.

 

[Speedskater]

You might find this 'RV Safety' blog of interest:

No~Shock~Zone is under construction

noshockzone.org

 

[hillbilly1]

Not sure if these are panel boards or not, but If so 408.36 would require the bus be protected at it's rating, and there is no exception for "sum of multiple breakers" (unless it's a service panel board).

Regarding the conductors themselves, 240.21(5) requires the outside tap terminate on a single OCPD.

That’s why I’m thinking they are considering it as a service, even though technically it would not be, but it also would be considered as a structure in some localities, so it would be required to have a grounding electrode at each pedestal.

 

[electrofelon]

That’s why I’m thinking they are considering it as a service, even though technically it would not be, but it also would be considered as a structure in some localities, so it would be required to have a grounding electrode at each pedestal.

I'm not very familiar with article 551 and if there is anything there that amends the usually rules.

 

[augie47]

551.75 Grounding. . (B) Grounding Electrode. Power outlets or recreational vehicle site supply equipment, other than those used as service equipment, shall not be required to have a grounding elec trode. An auxiliary grounding electrode(s) in accordance with 250.54 shall be permitted to be installed.

 

[zbang]

I just spent some time looking at catalog pages... AFAICT no manufacturer seems to specify a feeder overcurrent rating for any of their pedistals, they only say "200 amp 240/120v" or something like that and list the feed-though lugs as accepting larger sizes (often up to 1/0). My assumption here is that the listing covers feeding them from a loop with the larger OCPD (and I'm not sure how much ths bus rating really matters if there is no way to add breakers/taps to it).

 

[augie47]

I just spent some time looking at catalog pages... AFAICT no manufacturer seems to specify a feeder overcurrent rating for any of their pedistals, they only say "200 amp 240/120v" or something like that and list the feed-though lugs as accepting larger sizes (often up to 1/0). My assumption here is that the listing covers feeding them from a loop with the larger OCPD (and I'm not sure how much ths bus rating really matters if there is no way to add breakers/taps to it).

 

[kwired]

I just spent some time looking at catalog pages... AFAICT no manufacturer seems to specify a feeder overcurrent rating for any of their pedistals, they only say "200 amp 240/120v" or something like that and list the feed-though lugs as accepting larger sizes (often up to 1/0). My assumption here is that the listing covers feeding them from a loop with the larger OCPD (and I'm not sure how much ths bus rating really matters if there is no way to add breakers/taps to it).

Been a while since I have installed any of these, but I know I put them on a 200 amp feeder and seem to recall them being identified somehow as being rated for 200 amp supply/feed through. The actual bus that the breakers plug onto may very well been 125 amp design, but I think any instructions included in listing would be what matters.

 

[RD35]

Thanks everybody for the replies, discussion, and information. I will dig a little deeper into the mfg specs to see if there is a listing for this particular arrangement. Especially thanks for all the code sections to review. Very helpful info and much appreciated!