10ft NEMA 5-20P to 5-20R 20 Amp Extension Cord, 12 AWG SJT Heavy Duty, 125V, Black

A NEMA 5-20P to NEMA 5-20R extension cord moves a 20 amp outlet to where the equipment actually sits. Kitchens, garages, workshops and equipment rooms are often wired with a dedicated 20A branch circuit, but the receptacle ends up on the wrong wall. This cord carries that full 20 amp capacity across the room instead of forcing a drop down to a 15 amp cord and losing headroom.

The cable is 12 AWG x 3C SJT with 3.31 mm² stranded copper conductors and an 11.0 mm outer diameter. Twelve-gauge copper gives roughly 60 percent more conductor area than the 16 AWG cordage used in general-purpose household extension cords, which keeps voltage drop low over longer runs and limits conductor heating when a compressor, heater or large appliance draws near its rated current for extended periods.

Both ends are true NEMA 5-20. The 5-20P plug has the T-shaped neutral blade that only fits a 20 amp receptacle, and the 5-20R receptacle accepts both 5-20P and standard 5-15P plugs. Wiring is one-to-one — line to line, neutral to neutral, ground to ground — so there is no adapter, no reduction and no change in polarity between the wall and the equipment.

Typical loads include commercial and residential kitchen appliances, refrigerators and chest freezers, treadmills and other motorized fitness equipment, shop vacuums, bench tools, space heaters, and rack or bench equipment in a lab or server room that needs a 20A feed. Because these are sustained or high-inrush loads, the 12 AWG conductor and 105°C insulation matter more than they would on a light-duty cord.

The molded plug and receptacle carry c(UL)us file E210037-VN and the cordage carries UL and cUL file E204978, marked directly in the jacket along with the SJT, VW-1, FT2, 105°C and 300V ratings. All materials are RoHS compliant. The SJT jacket is an indoor thermoplastic grade — not the SJTW weather-resistant grade — so this cord should be kept out of wet locations and away from outdoor exposure.

The black jacket provides a professional appearance and suits standard data center and enterprise rack deployments.

Compatibility & Ordering Information: This cord fits any NEMA 5-20R wall receptacle or 20A power strip inlet and powers any device with a NEMA 5-20P or NEMA 5-15P cord end. It is not compatible with NEMA 6-20 equipment, which runs at 250V on a different blade orientation. Cable Leader lists PW143-12XX in several lengths; select the length on this page. Every Cable Leader cord is backed by our Lifetime Warranty.

Product Comparison: NEMA 5-20 20 Amp Cord vs NEMA 5-15 Standard Extension Cord

FAQ

What is the difference between a NEMA 5-20 and a NEMA 5-15 extension cord?

A NEMA 5-20 cord is rated 20 amps and a NEMA 5-15 cord is rated 15 amps or less. The 5-20P plug has a T-shaped neutral blade that only fits a 20A receptacle, while a 5-15P plug has two parallel blades. A 5-20 cord also uses heavier 12 AWG copper instead of the 14 to 16 AWG typical of 15 amp cords.

Can I plug a standard 5-15P device into this cord?

Yes. The NEMA 5-20R receptacle on this cord has a T-shaped neutral slot that accepts both 5-20P and standard 5-15P plugs. The reverse is not true — a 5-20P plug will not fit a 5-15R outlet, because the T-blade is intentionally keyed to 20 amp circuits only.

What gauge extension cord do I need for a 20 amp circuit?

Use 12 AWG for a 20 amp circuit. Twelve-gauge copper is the minimum conductor size rated to carry 20 amps continuously in a flexible cord, and it keeps voltage drop low enough that motors and compressors start reliably. A 14 or 16 AWG cord is not rated for a sustained 20 amp load.

Do I need a dedicated 20 amp circuit to use this cord?

The wall receptacle must be a NEMA 5-20R, which is only installed on a 20 amp branch circuit. The cord itself does not change the breaker rating — it carries the circuit's existing 20A capacity to the equipment. Plugging it into a 15 amp circuit through an adapter defeats the purpose and is not recommended.

Which 20 amp extension cord is best for indoor appliance use?

For indoor appliances, choose a 12 AWG SJT cord like this one — SJT is a thermoplastic jacket rated for dry indoor locations at 105°C. If the cord will be exposed to weather, moisture or outdoor use, choose an SJTW-jacketed cord instead; this cord is not rated for wet locations.