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Old 04-27-2008
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peteaeonix peteaeonix is offline
Former Bird Owner
Join Date: Jan 2008
Location: Ridgefield
Posts: 2,010

A "50 Amp" connection is 50 amps at 240 volts. In an RV, it's normally split into 2 legs of 50 amps at 120 v AC each. So you really have 100 amps at 120 volts with "50 amp service."

So, when you use "30 amp service" you get 30 amps at 120 volts or about 30% of the potential energy you'd have with "50 amp service." That's why it's so easy to overwhelm a 30 amp service with a WL. You're not lower by 20 amps -- you're actually lower by 70 amps!

As for the generator, it depends on its rating. Looking at the brochure listed on Vintage Birds, it appears you may have an 8kw Onan. That would suggest a total output of about 65 amps at 120 volts -- split in two legs of about 32.5 amps each. All generators are able to handle brief overloads (within limits) to accommodate motor startups, etc. so a 30 amp breaker (per leg) would likely blow before the generator was overloaded. At the very least, a delayed reaction breaker would be required to keep AC units and other electric motors from tripping the breaker. The electric heaters in various 'birds are only 10 to 12 amps each (mostly) but you may have had another load (battery charger or electric hot water element?) that you weren't aware of. So 2 electric heaters (12 amps each) leaves only 6 amps of load before a 30 amp breaker would trip. Battery charger or some other heating element (or microwave oven) might have tripped the breaker. The generator might have otherwise handled the load.

I would not plug in the two cords unless I fully understood the way they were wired up. You could end up 'blowing' circuits and appliances and/or burning up a lot of wiring both in the coach and the campground depending on what's hooked to what. If you have a hard-wired 50 amp cord, that is the one to use. If you need to plug into a 30 amp service, then use a 'dog bone' adapter as it splits the 30 amp 120 volt to both legs. Careful power management is required. (Some earlier year BBs had dual 30 amp cords as well as a 50 amp cord for use when few RV parks offered 50 amp service. It that case, you'd use <b>either</b> the 50 amp cord or both of the 30 amp cords.)

My coach is a few years newer than yours (and I have a much larger generator) but for shore power, I have a 50 amp cord (hard wired at one end to the coach) with the 4 prong "range" type plug.

I also have a 3 prong with side ground plug in the power compartment. I was told it was a "buddy plug" that I could access the generator power for external purposes. The only connectors I could find to fit it were dreadfully expensive ($150+) so I've done nothing to utilize that plug. I found (online) a diagram showing the standard wiring so I could have made up a plug/junction box to give me a 120V power tap -- but due to the cost involved, it isn't worth it to me.

Pete Masterson
(former) 95 WBDA 42'
(now) 2011 Roadtrek RS-Adventerous
Ridgefield, WA
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