Smartplug Converstion
First I give credit to the smart folks that posted on this 5th Wheel thread. https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/30084692.cfm Particularly this link: https://marinehowto.com...
Forum Discussion
IMO, the threaded locking ring problem with the STS twistlock plugs is the result of operator error. As we all know, overtime nonmetalic devices (plastic, pvc, vinyl, etc--all the things we have in our RVs) gradually gain resistance overtime and require a good cleaning and an occasional lube (spray silicone) to function properlty. The locking ring issues do not persuade me either way, rather it is all about safety (which includes avoiding potential future calamities).
If all the naysayers (it is not standard, not NEMA, not RV, no UL label on package...) take a breath for a moment and use our noggin, I think smarter heads can agree the problem with almost all plug failures are the result of one or both of the following:
1. Bad connection between the wire and the wired device.
2. Corrosion on the metal blades or contacts.
When it comes to terminal connection for plugs/receptacles, there are several varieties: Most common is the direct screw connection (wrap/loop wire clockwise behind the screw and tighten), and the less common terminal screw with lug (slip wire into locking lug and tighten terminal screw).
Can we agree the best option for 30/50 amp connection is terminal screw with lug? Why? Could it be the locking lugs provide greater amount of metal surface contact between wire and terminal.
OK, many of the circa 1938 twistlock plugs and all Smartplugs employ terminal screws with lug connection. So if I select the correct twistlock plug (with locking lugs), then Smartplug holds zero advantage. Both are winners on this test.
Now, we come to the metal blades of the two plugs. Which has greater metal surface contact?
The circa 1938 twistlock plug has tiny dimples to make electrical contact with a total surface area of 6.63 sq mm. Back of pin contact 1.3mm x 2.7mm = 3.51 sq mm, front of pin contact 1.3mm x 2.4mm = 3.12 sq mm.
Smartplug has a larger total contact area of 190.4 sq mm. Back of pin contact 16.4mm X 8.5mm = 139.4 sq mm, front of pin contact 6mm X 8.5mm = 51 sq mm.
Ok, 30 amp Smartplug has just over 183 sq mm greater surface area compared to circa 1938 twistlock, which I calculate to be about 27 times greater surface area (not 20 times).
So, now you have it; to reduce the chance of having bad blade contact and bad wiring, shouldn't one select the device having terminal screws with locking lugs and blades that have adequate metal surface to make electrical contact? Or should we be sheeple, and do what the other guy does and ignore progress (circa 2008 vs circa 1938).
LOL, it is not a solution in search of a problem--rather a multifaceted problem in search of a simple, single solution. I don't want bugs or critters walking up the power cord and nesting inside my TT (replace nondetachable cord with detachable cord). I don't want problems others are experiencing, burned out twistlock 30 amp plugs on their detachable cords (replace power inlet with Smartplug style).
If all the naysayers (it is not standard, not NEMA, not RV, no UL label on package...) take a breath for a moment and use our noggin, I think smarter heads can agree the problem with almost all plug failures are the result of one or both of the following:
1. Bad connection between the wire and the wired device.
2. Corrosion on the metal blades or contacts.
When it comes to terminal connection for plugs/receptacles, there are several varieties: Most common is the direct screw connection (wrap/loop wire clockwise behind the screw and tighten), and the less common terminal screw with lug (slip wire into locking lug and tighten terminal screw).
Can we agree the best option for 30/50 amp connection is terminal screw with lug? Why? Could it be the locking lugs provide greater amount of metal surface contact between wire and terminal.
OK, many of the circa 1938 twistlock plugs and all Smartplugs employ terminal screws with lug connection. So if I select the correct twistlock plug (with locking lugs), then Smartplug holds zero advantage. Both are winners on this test.
Now, we come to the metal blades of the two plugs. Which has greater metal surface contact?
The circa 1938 twistlock plug has tiny dimples to make electrical contact with a total surface area of 6.63 sq mm. Back of pin contact 1.3mm x 2.7mm = 3.51 sq mm, front of pin contact 1.3mm x 2.4mm = 3.12 sq mm.
Smartplug has a larger total contact area of 190.4 sq mm. Back of pin contact 16.4mm X 8.5mm = 139.4 sq mm, front of pin contact 6mm X 8.5mm = 51 sq mm.
Ok, 30 amp Smartplug has just over 183 sq mm greater surface area compared to circa 1938 twistlock, which I calculate to be about 27 times greater surface area (not 20 times).
So, now you have it; to reduce the chance of having bad blade contact and bad wiring, shouldn't one select the device having terminal screws with locking lugs and blades that have adequate metal surface to make electrical contact? Or should we be sheeple, and do what the other guy does and ignore progress (circa 2008 vs circa 1938).
LOL, it is not a solution in search of a problem--rather a multifaceted problem in search of a simple, single solution. I don't want bugs or critters walking up the power cord and nesting inside my TT (replace nondetachable cord with detachable cord). I don't want problems others are experiencing, burned out twistlock 30 amp plugs on their detachable cords (replace power inlet with Smartplug style).
