Okay, let's break down where to look for "factory sealed leads" markings on a motor and whether you need a seal-off fitting.

Where to Look for "Factory Sealed Leads" Markings

The location of these markings can vary depending on the motor manufacturer and the motor's design. Here's a systematic approach:1.

Motor Nameplate

This is the most common location. Carefully examine the nameplate for any of the following: The exact words "Factory Sealed Leads" or "Sealed Leads" A phrase like "Suitable for Class I, Division 2" (If it is rated for class 1 div 2 it needs factory sealed leads or sealed lead kit installed to be code compliant) Any mention of compliance with a specific standard that mandates sealed leads (e.g., UL 674, IEC 60079-0). Sometimes, there might be a symbol indicating sealed leads. Consult the motor's documentation to understand the symbol if you find one. Look for a T3C temp code on the nameplate to show it does not need a seal off.2.

Motor Housing Near the Conduit Box/Lead Entry

Inspect the area where the motor leads exit the motor housing and enter the conduit box. Look for small, stamped or engraved markings directly on the metal of the motor housing. The "Factory Sealed Leads" marking could be near the lead entry point.3.

Motor Documentation (Manual/Data Sheet)

If you have the original motor documentation, this is your best resource. Look for a section specifically addressing hazardous location installation or wiring. The documentation should clearly state whether the motor has factory-sealed leads and any specific instructions for installation in hazardous locations.4.

Inside the Conduit Box



Warning: Only open the conduit box if you are qualified and have de-energized the motor. Sometimes, a small label or tag is attached to the motor leads inside the conduit box, indicating that they are factory sealed. Inspect the way the leads are potted or sealed where they enter the motor housing from inside the conduit box. A factory seal will typically be a solid, molded material encasing the wires.

Determining If You Need a Seal-Off Fitting

The need for a seal-off fitting depends on these factors:1.

Hazardous Location Classification

What is the Class, Division, and Group of the hazardous location where the motor is being installed? (e.g., Class I, Division 1, Group D)2.

Motor's Hazardous Location Rating

Is the motor specifically designed and rated for use in that hazardous location? The motor's nameplate will indicate this.3.

"Factory Sealed Leads" or Equivalent

If the motor has factory-sealed leads and is properly rated for the hazardous location, you generally do not need a seal-off fitting immediately at the motor. The factory seals are intended to prevent the propagation of flames or explosions into the conduit system. If it is Class 1 Division 2 rated a seal off may be needed depending on the conduit system.4.

Conduit Run Length and Size

Even with factory-sealed leads, a seal-off might be required elsewhere in the conduit run, depending on the length and size of the conduit and the specific requirements of the applicable electrical code (NEC/CEC) for the hazardous location. Refer to the code requirements for conduit sealing. If the motor is in Division 1 locations it will need a seal-off regardless of having factory sealed leads.5.

Damaged Leads

If the factory sealed leads are damaged, a seal-off will be required.

In Summary


Thoroughly inspect the motor nameplate, housing, and documentation for "Factory Sealed Leads" markings.2. Determine the hazardous location classification.3. Understand the motor's hazardous location rating.4. Consult the applicable electrical code (NEC/CEC) regarding conduit sealing requirements.5. If you are unsure, err on the side of caution and install a seal-off fitting. It's always better to be safe than sorry when dealing with hazardous locations.6. If in doubt, consult a qualified electrician or electrical engineer experienced in hazardous location installations.Example

Let's say you have a motor installed in a Class I, Division 1, Group D location. If the motor is rated for Class I, Division 1, Group D and has "Factory Sealed Leads" clearly marked, you might not need a seal-off immediately at the motor, but you likely will need one depending on the overall conduit run. If the motor is not rated for Class I, Division 1, Group D, or if it doesn't have factory-sealed leads, you will need a seal-off fitting at the motor.

Important Safety Note: Working with electrical equipment in hazardous locations is extremely dangerous. If you are not a qualified electrician or electrical engineer with experience in hazardous location installations, do not attempt to install or modify any electrical equipment. Consult a professional. Flag for review