2-pole 30 amp breaker into two individual 120 receptacles?

Question

So i have a single 30 amp 240 volt dryer plug that is fed from this 2 pole 30 amp breaker. It has a breaker tie so it throws together. If i wanted to remove the plug and put quad 20 amp receptacles (two different circuits using each hot that I currently have in the box.) is this possible? I can remove the breaker tie, so it wouldn’t throw together, but with it sharing a neutral and being 30 amp breakers, I’m not sure if i can put the 20 amp receptacles.

Also the wire ran to the current box with the 30 amp plug is 10 guage, not sure if that would be fine with 20 amp receptacles?

Answer 1

The lack of a separate safety ground is a show-stopper. In fact, this circuit is unsafe, obsolete, and has been illegal in new construction for over 20 years - it is legal because it is grandfathered.

Regardless of whether you ever power something else here, the best thing you can do is search for an existing ground, and if absent, retrofit a #10 ground wire to this receptacle and change it to a NEMA 14-30 type recep (and the dryer to a NEMA 14-30 cord, while removing the onboard neutral-ground strap on the dryer).

Full stop.

You should do that, seriously. And then let 24 hours go by.

Once that is done and in your rear-view mirror...

Then, since there's already a ground here (it's not like you're adding the ground today), you can go three different ways to power your NEMA 5-15 plug-in loads.

1. You can fit a "Subpanel" here. Powered off that nice 4-wire feed, it can then have a subsidiary 30A breaker for the dryer as well as 15/20A breakers for your various 120V loads. That would be four breakers to get the most out of your 30A feed.

2. You can get a PDU (Power Distribution Unit) with a NEMA 14-30 cord. The PDU acts like a subpanel in terms of breakering.

3. You can remove that fat receptacle from the wall, and replace it with two normal NEMA 5-15 or 5-20 dual receptacles, with appropriate cover plate. But then, you will need to change the circuit breaker to 20A. Now, to wire the receptacles, you split with pigtails the grounds to both receptacles. You split with pigtails the netural to both receptacles. Black goes to one recep hot, red to the other.

Can't I just both retrofit the ground and convert the receptacles in one day? No. Since these new receps are effectively new work, it would need to be done to new-work standard with new cable homeruns, and you wouldn't be allowed to retrofit ground. You would only be able to exploit a retrofit-grounded dryer circuit if it was already like that.

Answer 2

20 Amp MWBC

This may be a good candidate for a 20 Amp Multi-Wire Branch Circuit.

An MWBC uses 2 hots + neutral + ground. The big question (as noted elsewhere) is ground.

1 - Replace 30 Amp x 2 breakers with 20 Anp x 2 breakers. Needs to be handle tied or common trip.

2 - Must have separate neutral and ground wires. You might not have that, need to check. A 3-wire dryer receptacle does not use ground, but there is a possibility that you have a ground wire ready & waiting. Metal conduit, if you have it end-to-end can be a substitute for a ground wire. If not then it gets a bit complicated - i.e., "retrofit ground and later replace the receptacle and breakers."

3 - Depends on location, but very likely you will need GFCI, either as part of the breaker or receptacles. Note that with GFCI you can't use "2 separate 20 Amp GFCI breakers". You either need a double 20 Amp breaker with GFCI (i.e., one unit that connects to both of the hots & the shared neutral) or you can do the GFCI at the individual receptacles after splitting neutral.

Answer 3

You can always use the oversized wire, you can pigtail on smaller wire if you have to. So if you replace the breaker with a two pole 20A you're all set.

But you can't use 20A receptacles on a 30A circuit, protected by a 30A breaker; the breaker is too big to protect the receptacles in the event of an overload. Not code compliant, not safe, don't do it.

Answer 4

I think you have to kinda square dance your way through the intent of the NEC, but 406.4(D)(2) says you can replace ungrounded receptacles "with a ground-fault circuit interrupter type recepacle(s)". It doesn't actually say same voltage/same amperage. The Code is subject to interpretation of the AHJ, so you might quickly lose, but you might not.

Again you need to change it to a two pole 20 amp breaker, you can't leave it on a 30 amp breaker, nor should you want to. If you had some little #16 AWG cord plugged in and it got pinched on a 30A breaker it could draw 60A for 2 minutes before tripping. On a 20A breaker should trip in less than 35 seconds. That could be the difference between a bad smell and a bad fire.

Also as others have said sharing the neutral creates what the Code calls a multi-wire branch circuit (MWBC), the code requires a two pole breaker or a listed handle tie.

Answer 5

We have changed these over. It appears that you have a 3 conductor #10. Black White and ground to this receptacle. You can't make this 2 separate circuits and use the bare ground as the grounded conductor(neutral) and the grounding conductor(ground). Since this would be a straight circuit, we would reduce the breaker to 20amps single pole and move the White conductor to the neutral bar leaving the Black conductor to the 20amp breaker. The bare ground will remain terminated to the ground bar. Use a breaker blank to fill the empty space in the panel. Now at the receptacle end make taps with #12 and go to each 20amp 120v duplex receptacle. Since this is now a straight 20amp circuit, you may be able to add a couple of extras if needed.