Welcome to my J.A.M. (Just Ask Mike) Session, a weekly column where I answer your basic electrical questions. If you’re a newbie who’s never plugged in a shore power cord (or ask – what’s a shore power cord?), or wonder why your daughter’s hair dryer keeps tripping the circuit breaker, this column is for you. Send your questions to Mike Sokol at mike (at) noshockzone.org with the subject line – JAM. This week I discuss the potential consequences ofresidential electricians miswiring a home 30-amp receptacle with 240 volts.
Don’t let this happen to you…!
I’ve had a bunch of emails and Facebook group posts this week about residential electricians miswiring a home 30-amp receptacle with 240 volts and frying the RV’s electrical systems. Here’s one example:
We have a 2021 Jayco 267BHS. I had an electrician install a 30amp outlet at home so we could plug in. In an excited and regrettable moment I didn’t think to use the surge protector. Plugged it in and saw a spark and pretty sure I heard a pop at the camper. Put surge protector on and took a picture to send to electrician, who called immediately to tell me to get it unplugged because he didn’t realize it was 120 and he ran it 240.
Unplugged, and everything seems to work fine on battery power. I noticed the AC circuit blew and I switched it back on and seems to work. I have not looked at any fuses at this point. Was away from camper for ten days due to family emergency. Batteries now dead and I used a dog bone to plug in to standard 110 outlet and there is nothing, no power to the rig. I connected to truck power and everything works. Has me feeling better that camper still works, but suspecting we’ve blown the power cord or whatever the connection is where shore power cord connects to unit.
- How bad is this?
- Can I consider asking the electrician to fix this? I don’t mean financially, but would this absolutely have to be a dealer issue or can it be repaired if we can troubleshoot and secure parts?
- Any other thoughts? I don’t even know where to access what I think might be the issue (thinking maybe under lower bunk or possibly remove underbelly?).
- Appreciate any thoughts about if I’m shut down at a dealer for a long time or it might be something I can handle on my own (or with electrician). The electrician is solid; just miscommunication.
There were many good answers in the Facebook thread, which I’ll sum up here.
- NEVER trust a residential electrician who may have never installed a 30-amp RV shore power outlet before.
- The RV TT-30 receptacle closely resembles the old 2-pole, 240-volt dryer receptacle.
- All 30-amp RVs require a single-pole, 120-volt service
- Depending on how many fancy electronics you have in your RV and what was turned on during this momentary application of 240 volts, it could fry the converter/charger, microwave, refrigerator, furnace controls, water heater controls, television and lots more. You might be lucky and only blew a few fuses, but I wouldn’t count on it. Think thousands of repair dollars to begin with.
Miswiring mistake was not due to client’s miscommunication
- This was not a miscommunication on your part as the TT-30 receptacle is plainly marked for 125 volts maximum. It’s up to the electrician to read all documentation and understand the circuit before he wires it.
- Your electrician is 100% responsible for this error and needs to pay for everything to repair it
- He may be able to replace everything for you, but you’re rolling the dice. There’s a lot of specialty wiring in an RV that your electrician may never have encountered before, and he’s already had one major failure. But you are correct that many dealerships are really busy and won’t have time to even look at your RV this season. So it could be bad either way.
For everyone else wanting a 30-amp receptacle at home:
Please read one of my dozens of articles I’ve written about this 240-volt issue and show it to ANY electrician before they wire a 30-amp outlet at your house. And always use an advanced/EMS surge protector, especially for 30-amp shore power. Read my latest article on this topic HERE.
And this is my JAM session on how to measure AC voltage with a digital meter. Read it HERE.
OK, everyone. Remember that electricity is a useful and powerful force, so we all need to pay attention to safety precautions while using it.
Let’s play safe out there….
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.
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