Conduit Bending - EMT and Rigid

Conduit bending is the one skill every first-year electrician is judged on. A tight, square 90 with no wrinkles, an offset that lands flush to the deck, and a saddle that clears the beam without a spec-sheet lookup - those are the bends that separate an apprentice who is going to stay from one who is going home. This guide walks you through bender anatomy, conduit types and wall thicknesses, the math behind every common bend, and the real-world gotchas that fail inspection.

Bender Anatomy

Every hand bender - whether it is a Klein, Ideal, Greenlee, or Gardner Bender - shares the same four features. Learn them by name:

• Hook (also called the handle-side catch) - The curved lip at the back of the shoe that grabs the conduit when you start the bend. The hook sets the back of your arrow mark when you bend a 90 from the back of the 90.
• Shoe - The curved body of the bender that wraps the conduit. The radius of the shoe determines the radius of your bend. EMT bender shoes are sized for thin-wall EMT; rigid/IMC benders have a deeper shoe and longer handle for the harder pull.
• Arrow - The triangular mark on the shoe. Your reference point for most offset and saddle bends. You line the arrow up with a pencil mark on the conduit to set where the bend starts.
• Star point - A star-shaped mark on some benders, typically used as a reference for back-to-back bends.

The handle is a lever. Step hard on the foot peg (the "kick pedal") at the base of the shoe and pull the handle smoothly. Do not jerk. Do not ride the handle down with body weight alone - foot pressure on the pedal is what presses the conduit into the shoe and prevents flattening.

Conduit Types and Wall Thickness

Three types cover almost all apprentice-level work:

| Type  | Full Name                 | Wall Thickness   | When Used                         |
|-------|---------------------------|------------------|-----------------------------------|
| EMT   | Electrical Metallic Tubing| Thin (0.042-0.083 in) | Most commercial, indoors, above grade |
| IMC   | Intermediate Metal Conduit| Medium (~20% lighter than rigid) | Outdoors, embedded, moderate protection |
| RMC   | Rigid Metal Conduit       | Thick (full rigid pipe) | Hazardous, buried, severe physical protection |

EMT is the lightweight gray tube you see running across commercial ceilings. IMC and RMC are threaded pipe, heavier and more expensive, used where the code or the environment calls for more protection. A 1/2 inch EMT weighs about 0.3 lb per foot; a 1/2 inch RMC weighs almost 0.8 lb per foot.

PVC (rigid polyvinyl) is the other common raceway, but it is bent with heat blankets or bent fittings, not a mechanical bender, so it is outside this guide.

The Three Bend Shapes

Everything a first-year apprentice does is a variation on three shapes:

• 90 (stub-up or stub) - Single 90-degree bend, usually to come up out of a floor and into a box or to turn a corner.
• Offset - Two equal-angle bends close together to jog the conduit over and parallel - used to enter a box that is not in line with the run.
• Saddle - Three (3-point) or four (4-point) bends that jog up and back down to go over an obstacle like a beam or another pipe.

Add a kick (a small 10-15 degree offset to enter a box a short jog off-plane) and you have covered 95% of residential and commercial field bends.

90-Degree Stubs - Stub + Deduct = Pipe Length

A 90 is the first bend every apprentice learns. The formula is simple and unforgiving:

Pipe length mark = desired stub height - deduct

The "deduct" (also called the "take-up") is the amount of conduit the bender eats up in the curve. It is stamped on the bender shoe for each trade size. Memorize these for EMT:

| Trade Size | Deduct (in) |
|------------|-------------|
| 1/2 in     | 5           |
| 3/4 in     | 6           |
| 1 in       | 8           |
| 1-1/4 in   | 11          |

Worked example: you need a 14-inch stub in 3/4 inch EMT to come up out of the floor into a junction box.

1. Deduct for 3/4 EMT = 6 inches.
2. Mark the pipe 14 - 6 = 8 inches from the free end.
3. Place the bender on the pipe with the arrow on your 8-inch mark, hook toward the free (stub) end.
4. Step on the foot pedal and pull the handle smoothly to 90 degrees. A floor mark or a bubble level on the handle confirms vertical.
5. The stub measures 14 inches from the floor to the outside of the bend. Cut the other end to length.

The most common first-week mistake is facing the bender the wrong way. Rule: the stub is on the hook side of a standard back-of-90 bend. Dry-fit once before you bend.

Offsets - Multiplier Table and Shrink

An offset jogs the conduit over by a known distance to clear an obstruction or enter a box that is not directly in line with the run. You pick an angle, and the angle determines how far apart the two bends sit on the pipe.

The multiplier is the distance between bend marks per inch of offset. Memorize:

| Angle | Multiplier | Shrink per in of offset |
|-------|------------|-------------------------|
| 10    | 6.0        | 1/16 in                 |
| 22.5  | 2.6        | 3/16 in                 |
| 30    | 2.0        | 1/4 in                  |
| 45    | 1.4        | 3/8 in                  |
| 60    | 1.15       | 1/2 in                  |

Worked example: 4-inch offset at 30 degrees in 1/2 inch EMT.

1. Multiplier = 2.0. Distance between the two bend marks = 4 in x 2.0 = 8 in.
2. Mark the pipe at your first bend reference and another 8 inches further along.
3. Shrink for 30 degrees = 1/4 inch per inch of offset. Total shrink = 4 in x 1/4 in = 1 inch. Add 1 inch to the overall pipe length so the finished offset lands where you want it.
4. Place the bender arrow on the first mark, bend 30 degrees.
5. Rotate the pipe 180 degrees in the bender (flip it over without changing direction), align the arrow with the second mark, bend 30 degrees again. The two bends now fold into a parallel offset.

"Shrink" is the amount the overall pipe length shortens because part of it is now jogging sideways instead of running straight. Ignore shrink and your offset will come up short; inspectors will not care, but the journeyman will.

Lower angle = gentler offset, longer bend separation, less shrink. Higher angle = tighter offset, less room taken, more shrink. 30 degrees is the workhorse - it is the default unless a tight space or a lower-profile look calls for something different.

Saddles - 3-Point and 4-Point

A saddle goes up, over, and back down to clear an obstacle (like a beam or another pipe running crosswise).

3-Point Saddle

A single center bend (typically 45 degrees) flanked by two outer bends half the center angle (22.5 degrees each). Used for lower-profile obstacles.

Formula for a 3-point saddle at 45 deg center:

• Center mark = location of the obstacle centerline on the pipe
• Outer marks = center mark plus/minus (obstacle rise x 2.5)
• Shrink = 3/16 in per inch of rise (at 45/22.5)

Worked example: 2 inch bump in the middle of a 20-foot run with a 45-degree center.

1. Mark the center of the obstacle on the pipe.
2. Outer marks sit 5 inches to each side (2 in x 2.5 = 5).
3. Add 2 in x 3/16 in = 3/8 inch to total pipe length for shrink.
4. Bend center mark 45 deg, flip, bend each outer at 22.5 deg.

4-Point Saddle

Two offsets back to back - four equal bends. Used for deeper obstacles (a full beam, a large pipe). Same math as an offset, doubled.

Kicks

A "kick" is a small offset (10-15 degrees) used to swing the end of a pipe a few inches sideways to enter a box or a coupling that is slightly out of line. Mark the kick at the box end, bend once at 10 degrees - you have just moved the pipe entry about 1 inch over for every 6 inches of run (multiplier 6.0 x 1 inch = 6 inches between bend and where the pipe was originally heading).

You will do more kicks in your first year than you will 90s. Any time a box ends up an inch from the pipe path because drywall moved or the framer was off, a kick saves the run.

Back-to-Back 90s

Two 90s used to jump a short distance in the same plane (think: up out of the floor, across a tight gap, down into a box). The math:

Distance between bend marks = finished back-to-back length

For a second 90, you use the back-of-90 method: reverse the bender so the hook is now at the other end and the arrow sits on your mark. The distance between the back of one 90 and the back of the next 90 is exactly what you measured. No deduct math on the second bend.

Concentric Bends (Parallel Runs)

Two or more pipes running side by side through a 90. Each pipe has a larger radius than the one inside it, or the inner pipes will end up longer than the outer and the run will go crooked.

Rule of thumb: outside-of-bend spacing = center-to-center spacing at the straight section. If your three pipes are 2 inches on center, each successive bend needs a 2-inch larger radius than the one beside it. This is what the segment bending (or "shot bending") technique is for - you bend smaller arcs at intervals around a mandrel to achieve a larger radius than the stock shoe. Most apprentices will not shot-bend in year one; you will just line up the shoe along the floor mark and accept the tiny misalignment, or use a hydraulic bender that has adjustable radius shoes.

Cutting and Threading Rigid

EMT cuts with a reciprocating saw, a hacksaw, or a pipe cutter. Ream the inside edge with a reamer or a half-round file - a burr will shred THHN insulation on the pull.

IMC and RMC require threads. The process:

1. Cut to length with a band saw or a portable chop saw (do not use a carbide tile blade - too brittle for steel).
2. Chuck the pipe into a manual die or a power threader (Ridgid 535, 700).
3. Lubricate generously with threading oil (dark thread-cutting oil, not motor oil).
4. Cut the NPT taper thread until the die is roughly flush with the pipe end (typical standard - about 0.75 inch of engagement for 1/2 inch; check the shop's threading chart).
5. Back off slowly. Wipe the threads. Check with a thread gauge or a ring gauge.
6. Hand-tight the fitting first, then two full turns with channel-locks or a pipe wrench.

Dope (thread sealant) on threads is required for wet locations. It also lubricates the assembly and, later, the disassembly.

Support and Strut

Secured conduit is safe conduit. NEC 358.30 covers EMT support:

• Within 3 feet of every box, cabinet, or termination.
• Every 10 feet along the run (or more often if the system calls for it).

NEC 344.30 covers RMC:

• Within 3 feet of every box/termination.
• Every 10 feet along the run (longer spans allowed for larger trade sizes per table 344.30(B)(2)).

Strut (Unistrut, B-Line) with beam clamps, pipe clamps, or two-hole straps is the standard. A "Kindorf" (1-5/8 inch) channel is the workhorse. Use the right size strap for the trade size - do not pinch a 3/4 inch conduit in a 1/2 inch strap "just because it fits."

Common Gotchas

• Wrinkles on the inside of the bend - You bent too fast, or the shoe is worn, or the conduit is under-supported. Slow down; check for scuffed shoe grooves; rebend.
• Flat spot on the outside of the bend - You did not step hard enough on the foot pedal. Foot pedal pressure plus smooth handle pull - the shoe presses into the pipe, the pipe does not flatten.
• Overbent past 90 - Your handle rotated past vertical. Either bend slower, or check the handle bubble level. Overbend is correctable by hand-pulling back 2-5 degrees, but past 5 degrees the pipe work-hardens and will crack if you push again.
• Cracked IMC on a cold morning - Steel embrittles below 40 deg F. Warm the pipe or wait for the sun on cold days. A crack on a threaded pipe is immediate scrap - you cannot mend it.
• Wrong direction of bend - Stub ended up pointing the wrong way, or the offset jogged toward the obstacle instead of away. Dry-fit every bend before you bend. "Measure twice, bend once."

Workmanship Standards

Every foreman has an eye. A run that is off by 1/4 inch at one end, jogs visibly at a coupling, or has offsets at three different angles down the same wall reads as sloppy even if every bend is functional. Standards:

• All offsets on a run at the same angle. If one is 30 deg, they are all 30 deg.
• Same-size conduit parallel on a wall lines up at the top or the centerline. Pick one and stick to it down the entire run.
• Couplings staggered if you have parallel runs. Three couplings in a row look lazy.
• Every bend clean, crisp, no ripples.
• Straps plumb and spaced evenly. The eye catches irregular spacing even if each strap is within code.

Good pipe is the one signal on a jobsite that tells every other trade - and every inspector - that the electrical contractor knows what it is doing. Apprentices who bend straight and clean get the trim callback; apprentices who do not get put on demo.

Day 1 Checklist

• Hand bender for the trade size you are running (1/2, 3/4, or 1 inch)
• Reamer or half-round file
• Tape measure, Sharpie, torpedo level
• Hacksaw or reciprocating saw with a metal blade
• Couplings, connectors, straps for the run
• Safety glasses. Always safety glasses.

Expert Tips

• "Read the deduct on the bender shoe. Don't guess." The number is stamped. Look at it.
• "Bend the first piece as a sample, then cut and bend the rest to match." Sample piece makes the whole run consistent.
• "A 10-degree kick saves a rough." When a box ends up an inch off-line, do not re-pull - kick it.
• "Cold steel cracks. Warm it up." Heat blanket, truck cab, or sun.
• "Smooth pull, not a yank." Bender mechanics work best with steady pressure.