I had a transfer switch replaced on my motorhome just before Thanksgiving. The tech did not use a torque screwdriver. A few weeks later I noticed stray voltage/hot skin condition. When the generator is running there is no stray voltage. It only occurs when plugged into shore power. Could improper torque of the screws cause the hot skin / stray voltage? Or do I need to look other places?
It’s possible that the technician didn’t connect the shore power ground conductor properly. Sometimes they forget to tighten the terminal screws at all so the ground wire is hanging loose. You need to measure the resistance between the RV chassis and the ground pin of your shore power cord. It should read very close to zero ohms. If not, then you need to trace the wires.
Thanks Mike! Great article and great information, but I have a concern.
Many (most?) RV electrical connections use a simple screw to clamp conductors. The conductors are deformed to some extent as the screw is tightened. Presumably, the inevitable deformation is considered when torque settings are established. However, deformation seems strongly dependent on the size of the conductors and the shape of the business-end of the screw. In many cases, I've seen small conductors that are very nearly severed by this process.
My concern: If one were to routinely loosen screws, then re-torque, doesn't one run a real risk of furthering conductor deformation and (possibly) completely severing conductors over time? Although this risk might be managed to some extent if exact torque specs are known, quality torques wrenches are always used, and torque wrenches are routinely checked for proper calibration. Unfortunately, even if all of these steps are rigorously followed, re-application of the proper torque would presumably result in a bit more deformation of the conductors. It seems like this problem could be made even worse if the conductors shift at all when the screw is loosened, which seems highly probable.
I completely agree that loose connections can be a very real problem possibly leading to arcing and overheating. Certainly something to be considered and addressed. However, any loss of conductors over time could also result in overheating as given electrical loads are sent thru fewer and fewer conductors. What do you think?
(It seems like this whole problem could be resolved if ALL conductors in RVs were secured in clamp-style connections. A screw is still needed to apply the clamping force in this type of device, but the conductors are shielded from direct screw damage by a smooth plate. I assume this would cost more than a simple screw connector, so I don't expect RV companies to willingly adopt this improvement unfortunately.)
Great article, but just want to add one point. You note safety first, so I would add “trust but verify”. I suggest always checking for power or current with a meter or voltage detector before touching anything! Thanks
Mike since you like to test all these devices what about another one being advertised called Miracle watt that will lower your electric bill by over 90%. Just plug it in next to your breaker box. Years ago a solar company sold me one saying it wold do the same thing and I couldn't tell any difference in the electric bill and just last week I saw it plugged in, I unplugged it and threw it away. should have sent it to you to test.
Wonder actually how accurate those torque tools are? How are they calibrated & where can you get it checked at?
Snoopy
Torque specs for Progressive Industries' EMS-HW30C is 22 inch pounds, per Kenny G., Tech Support Rep at Navico Group.
This reminder to retorque the terminal screws was helpful.
I just did this last year, but a season of travel has developed some puzzling sporadic opens and flickerings.
After the reminder, I retorqued all the screws in our WFCO power center, and immediately noticed the sporadic opens disappeared.
I had a transfer switch replaced on my motorhome just before Thanksgiving. The tech did not use a torque screwdriver. A few weeks later I noticed stray voltage/hot skin condition. When the generator is running there is no stray voltage. It only occurs when plugged into shore power. Could improper torque of the screws cause the hot skin / stray voltage? Or do I need to look other places?
It’s possible that the technician didn’t connect the shore power ground conductor properly. Sometimes they forget to tighten the terminal screws at all so the ground wire is hanging loose. You need to measure the resistance between the RV chassis and the ground pin of your shore power cord. It should read very close to zero ohms. If not, then you need to trace the wires.
Thanks.
Thanks Mike! Great article and great information, but I have a concern.
Many (most?) RV electrical connections use a simple screw to clamp conductors. The conductors are deformed to some extent as the screw is tightened. Presumably, the inevitable deformation is considered when torque settings are established. However, deformation seems strongly dependent on the size of the conductors and the shape of the business-end of the screw. In many cases, I've seen small conductors that are very nearly severed by this process.
My concern: If one were to routinely loosen screws, then re-torque, doesn't one run a real risk of furthering conductor deformation and (possibly) completely severing conductors over time? Although this risk might be managed to some extent if exact torque specs are known, quality torques wrenches are always used, and torque wrenches are routinely checked for proper calibration. Unfortunately, even if all of these steps are rigorously followed, re-application of the proper torque would presumably result in a bit more deformation of the conductors. It seems like this problem could be made even worse if the conductors shift at all when the screw is loosened, which seems highly probable.
I completely agree that loose connections can be a very real problem possibly leading to arcing and overheating. Certainly something to be considered and addressed. However, any loss of conductors over time could also result in overheating as given electrical loads are sent thru fewer and fewer conductors. What do you think?
(It seems like this whole problem could be resolved if ALL conductors in RVs were secured in clamp-style connections. A screw is still needed to apply the clamping force in this type of device, but the conductors are shielded from direct screw damage by a smooth plate. I assume this would cost more than a simple screw connector, so I don't expect RV companies to willingly adopt this improvement unfortunately.)
Thanks for your time!
A good reminder and helpful information. Thanks Mike.
Great article, but just want to add one point. You note safety first, so I would add “trust but verify”. I suggest always checking for power or current with a meter or voltage detector before touching anything! Thanks
True, that!
Mike since you like to test all these devices what about another one being advertised called Miracle watt that will lower your electric bill by over 90%. Just plug it in next to your breaker box. Years ago a solar company sold me one saying it wold do the same thing and I couldn't tell any difference in the electric bill and just last week I saw it plugged in, I unplugged it and threw it away. should have sent it to you to test.
Even the review site is a 100% scam! So it’s a scam site promoting a bunch of scam products. https://consumerreviewsite.com/pro-power-save/v2/pro-power-save-review.html?gclid=Cj0KCQiAnsqdBhCGARIsAAyjYjSzHvrYfEK2T8jin47VryZsgnGZauyh8aHh6G2be6CK9kDJfNTo_ysaAmGuEALw_wcB
Frank, I actually know all about these gadgets. Yup, they do absolutely nothing to lower your energy bill. More to write about!