After two years without an oven, I finally got a “new” one. A friend was re-doing her kitchen and decided to change to a gas stove, so gave me her four-year-old electrical one.
Today I confidently checked the plugs, and they were both the really big three-prong kind (just like on the dryer) so I hauled the old oven to the dump and set up to plug in the new one. . .
Only the plugs are different. The old one had three very large straight prongs, and the new one has two straight prongs and one that has a weird bend to the left. (And that’s the one that actually matches the dryer.)
So, my question is, are these things equivalent as far as the service is concerned? Is it just a matter of old/new plug style, and I can safely just switch out the outlet? Or should this be telling me that the line is not compatible with the new oven in some way?
Here are the NEMA plugs/outlets. The angled one is 30 amps. The other one in your picture is 50 amps. But the 50 amp and 20 amp plugs in the link look alike (about half way down the page).
For the others already answering, is there some way to tell them apart? Different blade widths maybe? OP should check the breaker for the outlet, to verify what amps they are for.
If the oven has a 30 amp cord then its fine to use a 50 amp cord to match the 50 amp receptacle.
However, you don’t want to put a 30 amp cord on a range that requires 50 amps. Trying to match a 30 amp receptacle. You’ll pop the breaker every time you turn on the oven or broiler. A situation like this would require hiring an electrician to run a 50 amp line into the kitchen.
Thanks everybody! So this looks fairly straightforward; with the possible exception of instruction 6. Is there any way to get the cord wrong way round?
Ground is in the middle, hot on the outside - so far I’m clear. But does it matter which prong goes on the positive and which on the negative? If so, how do I tell if I’ve got the cord right way up when I connect it? I’m accustomed to the wires being different colors, but this all the same plain grey. The center (ground) wire is smooth/printed on one side and seamed/textured on the other. It’s set smooth/printed side up. Is this a standard? Or does it not really matter?
Will my oven clock run backwards if I get it wrong? LOL!
the two outside wires are the hot wires and they are the same as each other. you want the terminals on the wire ends to have the flat side of the terminal towards the stove, the side with the wire towards the back.
look carefully at how the old one is attached and you want to do similar with the new.
Wow. So here I thought I understood this basic concept, but clearly I didn’t. I know all about the controversy, and Edison v Tesla, and poor Topsy the elephant. . . but I didn’t realize that alternating meant “from positive to negative” as opposed to “on, off, on, off.” All this time I thought those two prongs were + and - just like the terminals on my car battery, except they cycled on and off at a pace too fast for me to fathom.
Ignorance fought. This is what I love about The Dope. I am constantly confronted with my ignorance, then - almost simultaneously - it is defeated.
And thanks again everybody! I’m off to ACE hardware as soon as it opens.
Briefly, in your normal 110 volt outlet, the neutral is close to zero always, and the hot varies smoothly between positive and negative. In your 220 Volt plug, you have no neutral, but two hots both varying between positive and negative, with one always positive when the other is negative, and vice versa.
The neutral carries current, so it won’t be at precisely zero, so a ground wire is now included which doesn’t carry current, and is at zero.
That’s only one of the reasons why we use a separate safety ground.
The other big one is what happens during different types of faults. Something like an oven has a metal case. If you don’t connect it to anything (electrically) then if either hot wire shorts to the case, the case becomes hot and dangerous to touch. So it is better to ground the case. That way, if either hot wire shorts to the case it will just blow a fuse/breaker instead of becoming dangerous.
If you use the neutral as your ground connection though, you have two problems. The first, as ZenBeam said, is that if the neutral carries current it’s not going to be at true ground potential, which is an admittedly small shock risk, but it’s a risk. The second problem is what happens if the neutral breaks? Then, if you turn the oven on, the electricity has a path to the case (through the oven’s electrical parts and the neutral connection to the case) but not back to ground, and the case becomes electrically hot and dangerous to touch. So again, with a single fault, you can have a dangerous situation.
So we instead run a separate ground wire as a safety ground. If the hot wire(s) touch the case, it trips the breaker. If the neutral breaks, the oven just stops working. If the ground wire breaks, nothing bad happens. In any single fault, the case doesn’t become hot. It is therefore much safer, since it requires multiple faults before the case can become hot and dangerous (not impossible, but much less likely to occur).
Nah, better to change the oven to one with the right cord.
When I bought this house my friend left a lot of stuff in it. Stuff that was left in the house when he bought it. In the built-on storage trailer were a washing machine and a dryer. There was a washing machine in the laundry room, but my friend never moved the dryer in. I lived here a couple of years assuming the dryer didn’t work, and would go to a nearby trailer park to dry my clothes. Eventually I manhandled the dryer out of its storage spot, through the passageway, and next to the washing machine.
It had a four-prong plug, and the outlet had three prongs. I called an electrician to replace the outlet. After looking at the 70-plus-year-old wiring, fusebox, and meter, he said I’d need to have a lot more work done. Call him when I tear down the trailer and build a garage.
I went to the hardware store and bought a cord with a three-prong plug and put it on the dryer myself for about ten bucks.
with 4 prongs the dryer had a hot-hot-neutral-ground.
with 3 holes the receptacle of that age was likely hot-hot-neutral.
what you did might have got the dryer to work. as engineer_comp_geek stated you are leaving yourself with a risk by eliminating the grounding connection. the electrician didn’t suggest that option because it is not current safety standards.
You can always add a ground, and you should. This is easy to do it you have a voltmeter(or buy a cheap one). Older plugs tend to be Hot-Hot-Neutral but if the face plate is metal it may be a ground, check this by using the voltmeter(be careful) set the VM on ac 200v put the red probe into one of the hots and touch the face plate with the black probe( actually reverse this always ground first) if you register 120v+/- you now have a ground, go to home depot or the like and buy GREEN jacketed wire of at least 10guage, look for the green screw of the ground symbol on the back of the dryer, run the wire between the plate and the dryer and attach using the ground screw and the plate screw(its easier with crimp on loop ends), check for ground again from dryer side screw to the hot, check it again and there you go. This is just an overview and if the plate is not grounded you have to find another place to ground to, just send me a message and I will go into gross detail good luck and be careful
if you have a grounding conductor running from the fuse box to the receptacle then you have a grounding connection. with the age of the installation it likely could have rigid conduit or 3 conductor nonmetallic cable (with no ground).
if the electrician found a grounding conductor then they would have installed a receptacle that could accept a 4 pronged plug.