SOOW vs SJOOW Cable and Recommendations

SOOW and SJOOW are the best-rated cords for power tools and equipment. For belt grinders, let’s look at the difference between the two, plus the recommended wire sizes for your motors and Variable Frequency Drives. You’ll find the cable, strain reliefs and wire kits you need in our store.

SOOW vs SJOOW — what’s the difference?

SOOW cord has a 600-volt rating. SJOOW (the “J” is for junior service cord) is rated for 300 volts. Either works, but we recommend SJOOW for most grinder builds — it’s cheaper, and you don’t need a 600-volt rating for typical grinder motors and drives.

SOOW cord is incredibly durable. Its thermoset rubber jacket is weather-resistant and hardens under direct heat, leaving the cord unaffected by aging, abrasion, water, sunlight and ozone. Oil-resistant insulation adds to its durability. It can even be submerged and is flame-retardant, safe up to 221°F and flexible down to −40°F. The SJOOW version stays flexible and durable but is designed for indoor use — portable tools, equipment and motors.

Our cord recommendation

  • SJOOW (300 volt) — our first choice for indoor applications.
  • SOOW (600 volt) — our second choice, mainly due to cost.

Strain relief sizes

Use a strain relief at every connection into your motor and VFD.

  • 1/2″ strain relief — for 14/3, 14/4, 16/3 and 16/4 AWG.
  • 3/4″ strain relief — for 10/3, 10/4, 12/3 and 12/4 AWG.

Wire gauge by amperage

  • 14/3 or 14/4 AWG — rated for 15 amps
  • 12/3 or 12/4 AWG — rated for 20 amps
  • 10/3 or 10/4 AWG — rated for 30 amps

Check your motor amperage to determine the correct wire gauge.

Wire gauge for single-phase motors (cords up to 30′)

  • 1 hp, single-phase — 14/3 AWG
  • 1.5 hp, single-phase — 12/3 AWG
  • 2 hp, single-phase — 12/3 AWG
  • 3 hp, single-phase — 10/3 AWG

Wire gauge for 230 volt 3-phase motors with a KBAC-24D or 27D VFD

  • 15 amp supply — 14/3 AWG to the VFD, 16/4 AWG from the VFD to the motor.
  • 20 amp supply — 12/3 AWG to the VFD, 16/4 AWG from the VFD to the motor.
  • 30 amp supply — 10/3 AWG to the VFD, 16/4 AWG from the VFD to the motor.

Shop cable, wire kits & strain reliefs

Shop wire kits & cable →

Frequently asked questions

Should I use SOOW or SJOOW cord for my grinder?

For most indoor grinder builds, SJOOW (300 volt) is the better value and is plenty for typical motors and drives. Choose SOOW (600 volt) if you need extra durability or an outdoor-rated cord.

What wire gauge does my motor need?

Match the gauge to the amperage: 14 AWG for 15 amps, 12 AWG for 20 amps, 10 AWG for 30 amps. Check your motor’s amp draw and size the wire to match — a 1 hp single-phase motor typically uses 14/3, while 1.5 to 2 hp uses 12/3.

What size strain relief do I need?

A 1/2″ strain relief fits 14 and 16 AWG cord (14/3, 14/4, 16/3, 16/4). A 3/4″ strain relief fits heavier 10 and 12 AWG cord (10/3, 10/4, 12/3, 12/4). Use one at every connection into the motor and VFD.

What gauge runs between a VFD and the motor?

For 230 volt 3-phase motors on a KBAC-24D or 27D, 16/4 AWG runs from the VFD to the motor. The supply-side gauge to the VFD depends on your circuit — 14/3 for 15 amps, 12/3 for 20 amps, 10/3 for 30 amps.

These are recommendations only. Do your own research or consult a qualified electrician, and make sure all connections meet or exceed national, provincial and local electrical codes.

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