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RVelectricity – Torque values for circuit breakers


Hi Mike,
I’ve been reading some of your RVelectricity articles and recently about torque values for the ATS (automatic transfer switch). But what about the main 120 AC breaker box inside the RV? I’m worried about all those big circuit breakers in there. My power panel doesn’t say what the torque values should be on those breakers and I’m pretty sure they also need to be torqued properly.

What’s the torque supposed to be for those breakers? Thanks. —Martin

Dear Martin,
You’re in luck. Just in time for spring, here are the torque values for WFCO power centers, standard circuit breakers, and Southwire generator transfer switches. Other manufacturers should have similar values, but best to double-check if possible. But these torque values should be pretty standard for all similar products.

Safety First!

But first, make sure there’s no possibility of 120-volt power. And if you’re going to re-torque any of your 12-volt DC screws, be sure to disconnect the batteries so you can’t create a short circuit and melt a wrench, or get your wedding ring or metal bracelet trapped in the fault current path.


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What are the numbers?

Just remember these are all in inch-lbs of torque, NOT foot-lbs like your wheel lugs. You’ll want a torque-limiting screwdriver that can be set from 20 in-lbs to 60 in-lbs, and have the proper bits for each type of screw you need to re-torque. Also, back off each terminating screw a little, and then retighten them until the torque screwdriver clicks. You can get torque screwdrivers on Amazon HERE.

Loosen the torque driver when you’re done

After you’ve finished your yearly re-torque maintenance, you’ll want to back off the torque setting on the screwdriver to as low as it will go. This will prevent accuracy drift from the spring being under tension for months at a time.

Chart 1 on WFCO power centers

Chart 2 on standard circuit breakers


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Chart 3 on a Southwire Generator Transfer Switch

Let’s play safe out there….

Send your questions to me at my new RVelectricity forum here.

Mike Sokol is an electrical and professional sound expert with 50+ years in the industry. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.

For information on how to support RVelectricity and No~Shock~Zone articles, seminars and videos, please click the I Like Mike Campaign.

##RVT1043

 

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Glenn
6 months ago

Bad Amazon link in your article. Otherwise excellent.

Admin
RV Staff(@rvstaff)
6 months ago
Reply to  Glenn

Thanks, Glenn. I forgot to check that link last night. Have a great day. 😀 –Diane

RallyAce
6 months ago

Back in the 80s I took a course on installation and maintenance of industrial controls. We were told that, if no other information was available, to use 25 inch-pounds for terminal strips and 40 inch-pounds for control wiring to devices and never rely on ‘that feels about right’. We were also told that if the screw could take a square drive bit to use it as that was the correct bit for the screw. Looking at your charts, that looks to have been good advice.

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