Okay, I understand. You want to know if you can drill holes in a new, outdoor main breaker panel, similar to how it was done in a 1972 panel, to make the wiring easier. You're working under the 2017 NEC.

The short answer is: NO, you generally should NOT drill holes in a new electrical panel.

Here's a breakdown of why: UL Listing and Safety

Electrical panels are UL-listed (or a similar nationally recognized testing laboratory) as an entire unit. This listing certifies that the panel has been tested and meets specific safety standards. Drilling holes modifies the panel, which voids the UL listing. This means the panel is no longer certified to meet safety standards, and you assume liability for any problems that arise as a result of your modification.

Compromised Weatherproofing

Since it's an outdoor panel, maintaining weatherproofing is crucial. Drilling holes creates points where moisture, insects, and other contaminants can enter the panel. This can lead to corrosion, short circuits, and other dangerous conditions.

Potential Damage

You could accidentally damage internal components while drilling. Even minor scratches on wires or components can create future problems.

Code Violations

Modifying a listed electrical enclosure violates the NEC (National Electrical Code). An electrical inspector will likely fail your installation if they see unauthorized holes drilled into the panel.

Manufacturer's Warranty

Drilling holes will void the manufacturer's warranty.

Acceptable Alternatives

Instead of drilling, consider these alternatives:1.

Use Existing Knockouts

Panel manufacturers provide knockouts in various sizes for conduit and cable connections. Utilize these whenever possible.2.

Install Properly Sized Conduit

Properly installed and sealed conduit provides a secure and weatherproof pathway for wiring.3.

Hubs

Use hubs for large conduits on the top of the panel (if the panel is designed for hub installation).4.

Strain Relief Connectors

Use appropriate strain relief connectors for cables entering the panel to prevent stress on the connections.5.

Nipples

You can use conduit nipples to pass through the back of the enclosure if needed, but make sure to use listed fittings and ensure proper grounding and sealing.

Important Considerations



Read the Manufacturer's Instructions

Always consult the manufacturer's instructions for the specific panel you are installing. They will provide guidance on acceptable wiring methods and knockouts.*

Consult a Qualified Electrician

If you're unsure about the best way to wire your panel, hire a licensed electrician. They have the knowledge and experience to ensure a safe and code-compliant installation.

In Summary:

While it might seem like a quick fix to drill holes, it's a dangerous and code-violating practice. Use the approved methods for wiring electrical panels to ensure a safe and reliable installation. Prioritize safety over convenience. Flag for review