electricalreceptacle
I purchased a table saw that has a NEMA 6-15 plug. I have two outlets, one 14-50 and one 10-30. I was wondering what's involved with installing a new outlet that has a lower amperage and a different plug?
I can't seem to find any info online about this specific scenario. I've read that it's possible to install the new outlet and lower the amperage at the box, however I'm unsure if this is 100% accurate.
Any help would be useful.
Thanks!
Edit, adding photos: 
In a 120/240V single split-phase system, there's two ungrounded (hot), one grounded (neutral), and in most cases one grounding conductor. Measuring between the two ungrounded (hot) conductors should yield 240 volts +- 5%. Measuring between either hot and neutral, should read 120 volts +- 5%.
In the case of a NEMA 10-30. Each angled contact is one of the ungrounded (hot) legs, while the "L" shaped contact is grounded (neutral). Therefore, measuring between the angled slots should give you 240V. While measuring between either of the angled slots and the "L" shaped slot, should measure 120V.
As for plugging a NEMA 6-50 plug into a NEMA 10-30 receptacle, forget about it. NEMA 10-30 recepracles do not have a grounding conductor, whereas a NEMA 6-50 requires a grounding conductor. NEMA 10-30 is an nongrounded 120/240V device (hot, hot, neutral), NEMA 6-50 is a grounded 240V device (hot, hot, ground). A 10-30 receptacle will be protected by a 30 ampere breaker, and supplied by wires only rated to carry 30 amperes of current. If you plug a 50 ampere load, into a 30 ampere circuit. You will overload the circuit, and (hopefully) trip the breaker.
If you need a 50 ampere circuit for your welder, have a proper 50 ampere circuit installed by a licensed electrician.
You should NOT plug a 50 ampere device into a 30 ampere circuit!
Did I mix up wiring somewhere?
Yes.
All are working, BUT: Now, the outlet and light/fan are not hot until the dimmer switch is turned on. Furthermore the outlet and fan are reduced by the dimmer.
Apparently, you wired the outlet and fan in series with the dimmer.
Re-check your wiring and make sure the outlet and fan are fed by the hot feed in the circuit NOT from the load side of the dimmer.
Good luck and stay safe!
Best Answer
You will need 3 wires.
What I mean by that is if your colors are black-black-white-bare, you must use the black-black as your conductors, bare as ground, and cap the white. You don't need to care which black is which on a NEMA 6 or 14.
Because you are using a 15A receptacle, you must get a 15 or 20 amp 2-pole breaker for your panel and fit it. Your two wires go on that. Ground to the ground bus, of course.
Then fit a NEMA 6-15 receptacle. You can use as many 6-15 receptacles as you want on the circuit, and they often come in a duplex. Also get the correct cover plate for your box. (If your breaker is 20A, you must use a minimum of two 6-15 receptacles, so get that duplex!)
Good chance the wires won't fit on the terminals. Get 8 inch lengths of copper 14AWG wires (12 AWG wires if a 20A breaker) and pigtail. You can use wire nuts or Alumiconns. If any wires are aluminum, definitely use Alumiconns. Aluminum wire is fine for large wires 4AWG and up, just terminate them properly.
Due to the 15/20 exception, you can use a 20A breaker instead. However: a) all your wires must be at least 12 AWG, including your pigtails. And b) you must either use NEMA 6-20 receptacle(s), or more than one 6-15, e.g. that duplex. 6-15 plugs will work in 6-20 receptacles.
What to do with that NEMA 10-30
NEMA 10 is bad news - it is the "death socket". It harkens back to the age before grounds, and provides two hots and a neutral. Sadly NFPA compromised with appliance manufacturers to allow them to ground the appliance to the neutral. Any trouble with your neutral wire will "float" the neutral at near 120V, and that electrifies the chassis. You should smash the 10-30 to smithereens and burn the pieces... and convert it to NEMA 14-30 (or anything else with a ground) ASAP.
But good news for you. First, you are allowed to retrofit grounds. You don't have to go all the way back to the panel, just to any nearby ground which is large enough (and comes out of the same panel). And look! Right next to the 10-30 is a 14-50 with a ground! That was easy.
Sometimes NEMA 10 circuits use cables with neutral carried as a bare wire wrapped around the two main conductors like a net. You're grandfathered! and can still use that as a neutral, make sure to wrap it with insulation so it can't contact the ground wire or box. Or you can sacrifice your grandfathering and use it as a ground for a NEMA 6. Your call.