Make my mind up

Mark E Smith

Member
Messages
190
Location
Arkansas
OK what do I need to do here, got a Fahrenheat 240v Garage heater coming in and the cord already arrived and seems a little like overkill. I have a 30a dual pole breaker, but for some reason my dad put in a 50a three prong plug, now the heater only requires a 30a breaker and 10-2 wire. The only pig tale I could find for this outlet (50a plug) was a 40a dryer plug, OMG this thing is huge...too use an analogy, I feel I am using a diesel truck to haul a 14 ft bass boat...way too much for the job. So.. do I use what I got and ignore the super thick pigtail and plug, or do I replace the plug outlet with a 30a as it should be and use a normal 30a pigtail and corresponding plug, I am confused, but really this pigtail and plug seems like way way too much to be using for such a small heater and 30a breaker. Some one help me out here, make up my mind for me...lol
 
The NEMA (National Electrical Manufacturers Association) code on most plugs (despite the manufacturer's part number) has several parts... what you are looking for is an L6-30P which breaks down to L for locking (slight twist keeps it from falling out), 6 for single phase 240 volts - two hot wires plus safety ground makes it a 3 prong plug; 30 for the 30 amp version - the prongs are different for different current capacities so you can't plug it in a wrong outlet; and P for plug. For the female end it is L6-30R for Receptacle. Available from Home Depot, Lowes, and many other stores for $10 to $25. For high current and voltage it is not small, but a lot smaller than a dryer plug
 
The NEMA (National Electrical Manufacturers Association) code on most plugs (despite the manufacturer's part number) has several parts... what you are looking for is an L6-30P which breaks down to L for locking (slight twist keeps it from falling out), 6 for single phase 240 volts - two hot wires plus safety ground makes it a 3 prong plug; 30 for the 30 amp version - the prongs are different for different current capacities so you can't plug it in a wrong outlet; and P for plug. For the female end it is L6-30R for Receptacle. Available from Home Depot, Lowes, and many other stores for $10 to $25. For high current and voltage it is not small, but a lot smaller than a dryer plug

I love the breakdown of the nomenclature - thank you
 
I ended up getting a 30a plug outlet and 30a dryer plug from lowes

http://www.lowes.com/pd/Utilitech-Appliance-Power-Cord/3151097

http://www.lowes.com/pd/Utilitech-30-Amp-Dryer-Power-Outlet/3775475

too replace the 50a stuff I had, got it wired up, the wall outlet had a three wire (black/red/white wire from the breaker 30a dual pole) ) I hooked up the white as a ground then the cord I hooked to L1 and L2 and ground to the case. Seems to work ok. Probably could have used the stuff I had, but that cord was way to thick, the 30a 10 gauge stuff while still pretty thick was much more manageable ....
 
Even though I already got this hooked up and running, I still want to understand this wiring/outlet stuff...lots of question like...the power cord I got says 10-3, but I see no ground (there is only three wires), I am using the white neutral as the ground attached to case ground lug from the third L shaped pin of the plug. I thought 10-3 meant it had hot-hot-neutral and a bare ground (4 wires) but this pigtail has only three hot-hot-neutral, which is what I needed my plug from the breaker has three wires. Bought based on sight, I needed three wires and 10 gauge this fit the bill, bought the plug to match same deal by sight looked like it would fit and said it was for 30amp...lol...probably not how you should shop for electronics, but what can you do...lol...seems to work

Also why is 10 gauge nomex wire so much smaller then any pigtail plug wire with plugs already attached, noticed when I changed the receptacle out that the wire (from breaker 3 wire 10awg black,red,white) wire was solid 10awg, but the plug wire was stranded 10awg and very large in comparison, this stuff in soooo confusing...starting to think the folks running the electrical standard are the same folks as the pharmaceutical company, they like to make things confusing too...lol

last, whats the deal with poles and why would I need a separate neutral/ground if they both go to the same buss bar in the breaker panel

I probably will be ok with what I have setup, don't feel like spending another $79 for a service call just to have an electrician come out and spend 30 sec and say your fine...lol...but anytime I get into a situation were I no little to nothing about what I am doing...I become obsessed with worry
 
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The 10g stranded is both bulkier because of the strands and also because of how it's expected to be used there is a lot more/more complicated insulation to keep it from overheating. You need the standard though for anything where you move the wire around because the solid will work harden and break.

The"neutral" is the return path for 120v. For 240v the two hot wires are out of phase so the difference between the peaks is twice as high as the difference between one of them and the ground/neutral (thus 240 vs 120).

The ground wire is the emergency return path. For 240v you don't need a neutral because you're using the delta between the hours but you do need the emergency return path in case some voltage leaks to the components. For 120v, same basic idea. The idea is to present a "shorter" path to any electrical faults than the user provides. Most of the electrical safety mojo is to help keep the user from being the shortest path.
 
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