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Onan: Rigging up 4.0 RV BFA

Dave85

Registered
I have a 4.0 RV 4kw generator. It’s not in the RV anymore. I’ve got it running now and have it on a cart. I’m trying to figure out how to wire it up. How many plugs should I run with it? Do I need a breaker panel of some kind? I’m new to working with generators and I’m not an electrician.

The model number is:
4.0BFA-1R/16004C

Serial:
C843755097
 

Zeromedic

Subscriber
Last Subscription Date
03/08/2020
Hi Dave,

Small world. I once had a 4kw Onan BFA, single 30+ amp 120v only just like yours. Mine was 1980 vintage.

If I still had it, I would run the output 10 gauge stranded (or 12) direct to a good "spec" grade duplex receptacle.
Even better, find one rated for 20 amps.

Then plug a pair of cheap power strips that have 11-13 amp switch/breakers into each outlet. Load as desired.

One or both power strips can be moved to more convenient locations with -good- quality extension cords.

I run a 12 gauge 40 ft contractor grade extension cord into the kitchen. Microwave runs fine, normal load is just
the refrigerator. Coffee maker as needed. The other feed is a 100 ft orange cord to wherever needed. Mostly left
feeding sat/dsl/wifi and tv's computers chargers led lights.

Steve
 

Dave85

Registered
Hi Dave,

Small world. I once had a 4kw Onan BFA, single 30+ amp 120v only just like yours. Mine was 1980 vintage.

If I still had it, I would run the output 10 gauge stranded (or 12) direct to a good "spec" grade duplex receptacle.
Even better, find one rated for 20 amps.

Then plug a pair of cheap power strips that have 11-13 amp switch/breakers into each outlet. Load as desired.

One or both power strips can be moved to more convenient locations with -good- quality extension cords.

I run a 12 gauge 40 ft contractor grade extension cord into the kitchen. Microwave runs fine, normal load is just
the refrigerator. Coffee maker as needed. The other feed is a 100 ft orange cord to wherever needed. Mostly left
feeding sat/dsl/wifi and tv's computers chargers led lights.

Steve
Sounds like a good plan to me. Thanks for the advice.
 

Zephyr7

Registered
I like to mount a twistlock (won’t loosen or fall out with vibration) in a box on the genset, then use a heavy cable with a twistlock end to feed a small distribution box (basically a converter to give “regular” outlets instead of twistlock) on the end. After that, I’d do as Steve mentioned with cords and plug strips.

Note that if you have a 30A supply and are using regular outlets, you’re really supposed to use 20A breakers to feed them. You can use a small electric panel on a piece of plywood for this purpose, with a few outlet boxes mounted on the same piece of plywood. Commercial power distribution boxes are also available for this purpose but they tend to be expensive. Another option is to use a larger box and some small airpax breakers in holes drilled in the cover. There are lots of easy to do it, just use good quality components and be safe.

Bill
 

Ben Cowan

Subscriber
Last Subscription Date
12/07/2019
Got several,have one on the output end of a 5 conductor 10 gauge wire on my 7.5 JB for temporary use. Would be a good fit for the 4.0
 

Zephyr7

Registered
How thick and durable is that back of that box? For $9 it’s worth a gamble I suppose if no one knows. Just blank out the connector on the back and use a cable gland on one end to install a pigtail or SO cable with a male twistlock (L14-20P or L14-30P) and you’re good to go.

Bill
 

Ben Cowan

Subscriber
Last Subscription Date
12/07/2019
Check in with Max , if I remember right we both bought several some 2-3 years ago. for exactly such an application. the boxes are pretty strong. i put one on a 6.5 rv unit so i could use the 240volt outlet to power an old welder I have. For the price you cant buy the components individually. at least in my opinion. I know they are not top shelf quality but for intermittent use should be pretty good. LUck, Ben
 

Dave85

Registered
I mounted my 4 kw in a box on my RV hauler. I had a electrician wire it up for me. He said you absolutely need a breaker box. I have several outlets in the cab and on the bed, and a camper plug.
You can do the same thing but on a cart.
That’s a very legit setup. Thanks for the ideas.
 

Dave85

Registered
So I’ll order those breaker panels for 8.99 and mount them. That’s the plan. I did wire an outlet to the generator today to make sure it does in fact make electricity. It seems to be making 140 volts? Wondering if that means it’s running too fast. I got 118 volts in the wall outlet in my garage.
 

nothingbutdarts

Sponsor
Last Subscription Date
08/15/2019
So I’ll order those breaker panels for 8.99 and mount them. That’s the plan. I did wire an outlet to the generator today to make sure it does in fact make electricity. It seems to be making 140 volts? Wondering if that means it’s running too fast. I got 118 volts in the wall outlet in my garage.
These are worth their weight in gold when working on a generator: https://www.ebay.com/i/233500143699...MIt_fHwOa96AIVjozICh1yXwcXEAQYAyABEgLef_D_BwE

The voltage on your set is regulated by RPM, 1800 RPM is 60HZ frequency, no load HZ should be about 61.5HZ
 

Dave85

Registered
Okay, thanks for the advice. Next time I get an off day I'll try to lower the rpm and see what effect that has on the output. Next time I go to Harbor Freight I think I might pick up a better multi meter. I don't think mine reads Hertz and it'd be good to have a better one anyway.
 
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