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3-prong 'dryer' plug
Dave Garoutte:
In a venue walk-thru today, I have a choice of a 240v three prong dryer plug or a couple of Edison 120v circuits.
I am guessing the 240v supply can't be split into two 120v in my distro, which has a 4-prong plug, since there is no common wire.
I have run this PA off of a 20 amp 120 circuit before with no problems.
Tim McCulloch:
--- Quote from: Dave Garoutte on August 04, 2017, 10:01:08 PM ---In a venue walk-thru today, I have a choice of a 240v three prong dryer plug or a couple of Edison 120v circuits.
I am guessing the 240v supply can't be split into two 120v in my distro, which has a 4-prong plug, since there is no common wire.
I have run this PA off of a 20 amp 120 circuit before with no problems.
--- End quote ---
For sure the 30 Amp plug is missing either a neutral (most likely) or the EGC and you're correct that makes it a no-go.
Jeff Bankston:
3 prong dryer plug = Hot Hot Ground , no neutral.
Jonathan Johnson:
--- Quote from: Jeff Bankston on August 04, 2017, 11:53:31 PM ---3 prong dryer plug = Hot Hot Ground , no neutral.
--- End quote ---
Or hot-hot-neutral with no ground.
Three-prong dryers were wired internally with a bonding jumper between the neutral and the chassis. This is no longer considered acceptable.
Cailen Waddell:
--- Quote from: Jonathan Johnson on August 05, 2017, 02:09:06 AM ---Or hot-hot-neutral with no ground.
Three-prong dryers were wired internally with a bonding jumper between the neutral and the chassis. This is no longer considered acceptable.
--- End quote ---
Fwiw - not always. I know of at least one old school dryer without the fancy electronics that didn't need a neutral. Just two hits and a ground. There was nothing in it that didn't run on 240v....
But yes - the internal bonding is not acceptable.
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