Because of winter's extreme temperatures and freeze/thaw cycles, you may be replacing exterior PVC-coated conduit this spring. But errors in replacing raceway can result in problems rather than provide an effective repair. Plan to pull new conductors instead of reusing the existing ones. It's risky to subject conductors to the stress of removal and re-pull, and it takes far fewer personnel hours to use factory-spooled conductors than to re-spool used conductors or work from piles of wire.

Before scheduling replacement:

  1. Estimate the job duration. Get approved dates from operations.
  2. Evaluate the work area for all requirements, including lighting, ventilation, access, and working space.

Before disconnecting anything:

  1. Verify you have an updated set of "as-is" drawings. This involves point-to-point resistance checks or signal tracing.
  2. Inspect terminals for hotspots. Now may be a good time to replace terminals or termination devices.
  3. Examine related hardware, such as switches, panels, and boxes for serviceable condition. Replacing now, rather than only a few months after you’ve terminated the new wiring, saves money.

Before removing the existing raceway:

  1. Examine the existing routing to see if changing it makes sense. If so, now is the time to make that change.
  2. Note any bonding deficiencies, support issues, or clearance issues you may correct with the new installation.
  3. If the affected run is for a critical circuit, have the complete bill of materials on hand.