I bought a new dryer that has 4 prong L cord but outlet we have is 4 prong and straight. Should I change outlet or the cord? How easy is to swap out outlets?
If it is fed by a 50A breaker then you need to change the breaker to a 30A breaker and then change the receptacle also to a 14-30R.
If it is fed by a 30A breaker leave the breaker and change the receptacle.
I think there is an odd NEC provision (210.21(B)(1)) that allows a single 50A receptacle on a 30A breaker, so someone might recommend changing the cord, but that would likely conflict with the Installation Instructions which likely say to use a 14-30 or 10-30 cord. The Instructions are part of the UL (or CSA/ETL/TUV) Listing and the NEC requires complying with them. And the 50A cord will be bulky and hard to work with.
I assume we are dealing with a consumer-tier dryer in the sub-$1500 range, not a commercial laundromat unit.
The correct receptacle for a dryer is NEMA 14-30, which requires a 4-wire connection. Also acceptable is:
- 14-30 hot-hot-neutral, mounted on a metal junction box which is grounded via a wire or the use of metal conduit back to the panel. The socket picks up ground via the metal box.
- 14-30 hot-hot-neutral, which is ungrounded, protected by a GFCI back at the panel, and marked "No Equipment Ground".
- You cannot use a 3-prong NEMA 10. You can continue in service one which was installed prior to 1996, but it's not a great idea.
If the dryer cord is not NEMA 14-30, or has an inconvenient bend, the correct answer is to change the dryer cord. Note that if you are changing from the terrible NEMA 10, there is a procedure you must follow to separate chassis ground so it is no longer bootlegged off neutral. (yes, that's as scary as it sounds).
Every once in a blue moon we see people use 50A receptacles on dryers (NEMA 14-50 or 10-50). That is wrong and a Code violation. Change it at once.