Conduit Sizes Chart

Cable is often routed through conduit or trunking during installation. When pulling a cable through a conduit, friction between the wires and the conduit walls can make it challenging to draw the cable.

Cable failure and wasted time can be avoided by predicting how many cables can be hauled through the conduit. Furthermore, heat can be generated by increased current signals traveling via cable. If too many of these wires are inside a conduit, the heat created can cause a fire.

When you split a piece of conduit in half, you’ll see that the interior and outside diameters differ due to the thickness of the conduit wall material. As a result, the conduit is known in the AV industry for its “trade size.”

This could apply to the pipe’s inner or outer diameters; commonly, the approximate outside diameter is referred to as “trade size.” (Read Curtain Sizes Chart)

EMT Conduit Sizes

Conduits come in a variety of shapes and sizes, including electrical metallic tube (EMT), intermediate metal conduit (IMC), rigid metal conduit (RMC), flexible metallic conduit (FMC), and polyvinyl chloride (PVC) conduit.

In our guide, you can check the EMT conduit sizes chart to ensure you are not overloaded.

By the end, you’ll find EMT dimensions; the conduit you have is in accordance with code, and the power inside will be supported when in use.

What Size Does Conduit Come In?

Conduit comes in conventional sizes of 1 m2, 2 m4, 1 m2, and 4 m2. Conduit diameter is typically measured in millimeters outside the United States and is determined by its diameter.

Therefore, 20mm, 25mm, 32mm, 40mm, and 50mm are typical metric outside dimensions. Electrical metallic tubing can have the same dimensions as PVC but will be harder to work with because of weight.

EMT Conduit Sizes Chart

Conduit Trade Size Outside Diameter Inside Diameter Max Support Distance
Rigid Metal (PVC)
1 1/4351.51038.41.38035145
1 1/2411.74044.21.61040.9145
2 1/2632.87573.02.46962.7166
3 1/2914.000101.63.54890.1207

Is Electrical Conduit Measured By ID or OD?

The exterior diameter of the tubing is stated in inches. Conduit manufactures rigid PVC conduit and fittings and PVC utility ducts.

In line with the National Electrical Code, PVC conduit and duct has been proven robust and effective for years of maintenance-free use in underground, encased, and exposed applications for commercial, industrial, and utility applications.

  • Commercial, industrial, and utility applications are all possible.
  • Resistant to corrosion in extended use
  • Non-galvanic and non-magnetic
  • It is self-extinguishing.
  • Impact Resistant
  • Corrosion-resistant
  • PVC is chemically resistant and usually unaffected by acidic soils or salts.
  • PVC Conduit has superior insulation properties and no power loss or conductor heating.

Services Where PVC Exceeds Requirements

  • Important lines for cable, data, and communications
  • Buildings for businesses and industries
  • Residential and commercial applications
  • Underground based conduit feeds streets and highways
  • Treatment plants for water and wastewater

All wiring should be run via rigid PVC conduit and secured with the appropriate fittings according to data and important information referenced that meets code requirements.

Straps must be used to securely attach and support exposed conduit if a junction box isn’t in use. The straps must be typically be installed according to the National Electric Code (NEC) prescribed spacing for any conduit size of electrical metallic tubing or ones made of PVC.

What Sizes Does EMT Conduit Come In?

Pulling cable is only half of the task for electricians. They must first construct massive networks of electrical conduit before they can begin installing the wiring.

Electricians typically run many cables via a single raceway, so knowing how much room is available inside the duct is critical. Unfortunately, this isn’t always obvious at first glance.

The internal diameter of rigid metal electrical conduit does not always match the trade sizes. Worse, unmarked conduit bundles can arrive on-site, and it’s difficult to determine the difference between 1.25- and 1.5-inch conduit with the naked eye. (Learn How To Turn Off Hard Wired Smoke Alarm)

For example, according to experts:

  • The internal diameter of a 0.5-inch metal conduit is 0.622 inches.
  • 0.75-inch rigid metal conduit has an internal diameter of 0.824 inches. You’ll discover this is typically the smallest EMT conduit dimensions for tubing suggested for raceways in residences and industrial structures.
  • The actual inner diameter of a 1-inch conduit trade size is 1.049 inches.
  • The internal diameter of 2-inch lengths is typically 2.067 inches.

These standards apply to rigid metal conduit (RMC), the thickest metal raceway available.

While the thick walls and zinc coating on galvanized steel conduit provide excellent mechanical protection, they reduce the amount of available inner space.

The trade size of a length of RMC, a piece of intermediate metal conduit (IMC), and metallic electrical tubing might all be the same (EMT).

However, clearance varies slightly between products. Even from one length of conduit to the next, items from various manufacturers may have minor variances.

Any difference in inner diameter can pose issues when joining cables or planning how many you can pull in a single run.

So, given all of these considerations, what is the best method for measuring the length of the raceway before installation? A gauge is handy to have, or you can use one of the charts on offer.

EMT Conduit Trade Size Table

Size (inches)EMT DecimalEMT FractionIMC DecimalIMC FractionRigid DecimalRigid Fraction

The inner wall-to-wall diameter of any conduit section may be reliably measured with these simple triangle measurement instruments.

While the BHS all-steel Electrical Conduit Gauge was developed to measure the inner diameter of steel and aluminum conduit, it may also be used to measure the inner diameter of PVC and flexible conduit when used correctly.

The Electrical Conduit Gauge precisely measures tubing with a diameter of 0.5 to 4 inches. Measurements are laser-engraved into corrosion-resistant stainless steel, ensuring obvious trade size recognition for conduit in even the harshest industrial conditions, without the risk of markings becoming obliterated over time.

With an Electrical Conduit Gauge, a conduit cutter, and a bending tool in your toolbox, you’ll be ready to install intricate runs wherever the work calls for it.

Conduit maximum number of wires

Conduit Filling Capacity Limits

The maximum number of wires that can be placed inside a conduit depends on the conduit’s kind and size and the size of the conducting wires.

The American Wire Gauge, or AWG, the number determines the size of a wire. The wire diameter increases as the AWG number decreases.

The fill capacities for THHN insulated wire, the most common type of wire used in the conduit for domestic circuits, are:

Conduit Fill Table

Size and Type of Conduit14 AWG Wire12 AWG Wire10 AWG Wire8 AWG Wire
1/2-inch EMT12953
3/4-inch EMT2216106
1-inch EMT3526169
1 1/2-inch EMT84613822
1/2-inch PVC—Sch 4011853
3/4-inch PVC—Sch 40211594
1-inch PVC—Sch 403425159
1 1/2-inch PVC—Sch 4082593721
1/2-inch PVC—Sch 809642
3/4-inch PVC—Sch 80171274
1-inch PVC—Sch 802820137
1 1/2-inch PVC—Sch 8070513218
1/2-inch FMC13963
3/4-inch FMC2216106
1-inch FMC3324159

Conduit Sizes Chart

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