I have a 50Amp to 15/20Amp T-Blade extension cord. Here is the link.

The 50Amp end is plugged into an unused Stove outlet.

When I plug in a surge protector the extension cord does not seem to work. The 3-prong surge protector does not have a T-blade connector. I also tried plugging in 2-prong fan, but this doesn't work either. No household device that I tried works.

If I use a Voltmeter I see 118VAC at the end of the extension cord. When I plug in the surge protector the protected and grounded lights both turn off. These lights are normally on when plugged into a standard wall outlet. However, I see 118VAC when I plug the voltmeter into the surge protector outlets.

Am I wrong to expect to be able to plug in household devices to this extension cord?

Does the device need to have a T-blade connector?

UPDATE: The measured voltage between the 50A socket ground and a nearby 15A socket ground is 0.01V.

@brhans is right. When I measure between the T and the straight it is 105V (nothing plugged in) and changes to 240V (w/ fan plugged in).

I am assuming that he is also correct that a neutral line is missing.

What is the correct way to fix this?

  • Plug something simple like a bedside lamp into one side of your T-Blade and turn it on. If it doesn't light up, leave it plugged in and turned on and measure the voltage at the other side of the T-Blade. $10 says you'll see around 240V ... – brhans Dec 6 '17 at 2:41
  • Is the 50A stove outlet actually grounded? Or did they slap a NEMA 14-50 where a NEMA 10-50 once was, and call it "good"? – Harper - Reinstate Monica Dec 6 '17 at 3:21
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    Wow, $95 and all the code violation you could ever ask for. I don't see any mention of 20A circuit breakers on this thing, so it's putting 50A into receptacles that should never have more than 20A feeding them. Not a fan... – Ecnerwal Dec 6 '17 at 3:27
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    It sounds like the 50 amp receptacle is mis-wired. Double check the wiring on the 50 amp receptacle and verify all voltages on that end first. – ArchonOSX Dec 6 '17 at 10:48
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    I meant you should measure between the T and the straight, not from ground to each one. I think you have a missing neutral at your outlet, and plugging the lamp on one side will then highlight this by giving you (L1 + L2) = 240V on the other side. – brhans Dec 6 '17 at 11:57

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