110.75 - ACCESS TO MANHOLES

Or: "How Not to Get Stuck Like Winnie the Pooh in a Utility Hole"

The Real Deal

Look, nobody wakes up dreaming about crawling into a concrete hole in the ground. But if you're gonna do underground electrical work, you better be able to get in AND—here's the important part—get back out, especially if something goes sideways down there.

This section is all about making sure manholes are actually human-accessible, not just "theoretically possible to squeeze into if you exhale really hard and leave your tool belt behind."

(A) Dimensions - Size Matters (That's What She Said)

Rectangular openings: Minimum 26" × 22"
Round openings: Minimum 26" diameter

Think of it this way: If you can't fit a medium pizza box through the hole, you probably can't fit a sparky with a tool belt either.

EXCEPTION - The "Skinny Hole" Clause:
You can drop down to a 24" (600mm) round opening IF:

There's a fixed ladder that doesn't block the opening, AND
The manhole ONLY contains the wimpy stuff:
- Fiber optic cables (the IT nerd stuff)
- Fire alarm circuits (power-limited per 760.121)
- Class 2 or Class 3 control circuits (725.30)
- Class 4 fault-managed circuits (725.50)

Translation: If there's actual POWER down there—you know, the stuff that bites—you need the full-size hole. If it's just low-voltage communication stuff that couldn't power a nightlight, you can get away with the smaller opening, but only if there's a ladder.

(B) Obstructions - No Booby Traps

The opening has to be free of stuff that'll stab you, snag you, or otherwise ruin your day when you're trying to get out in a hurry.

No sharp edges, no rebar sticking out, no conduit elbows positioned perfectly to catch your belt buckle when there's smoke pouring out behind you. Your escape route shouldn't feel like an obstacle course on American Ninja Warrior.

(C) Location - Don't Stand Where You'll Land on the 13.8kV

The opening should be positioned so you're NOT climbing down directly onto energized equipment.

Imagine coming down a ladder in the dark and your boot landing on a busbar. Spoiler alert: That's a bad Tuesday.

When you CAN'T avoid it (because real life isn't perfect), you need EITHER:

A protective barrier (something between you and the danger candy), OR
A fixed ladder (so you're not free-falling onto switchgear)

(D) Covers - Heavy Enough That Teenagers Can't Steal Them

Manhole covers must be over 100 pounds OR require tools to open.

Why? Because we don't want random people popping them open for fun, copper thieves helping themselves, or some drunk college kid thinking it's a shortcut.

CRITICAL: The cover has to be designed so it can't fall into the hole or drop far enough to hit conductors or equipment. Nothing says "code violation" like a 150-pound cast iron lid doing a cannonball onto your 480V switchgear.

(E) Marking - Label Your Holes, People

The cover needs an identifying mark or logo that screams "ELECTRIC" (or similar).

Because manholes can look alike, and we really don't want the water department popping open our vault looking for a shut-off valve. Also helps firefighters know what they're dealing with when they show up.

Pro tip: "DANGER - ELECTRIC" works better than a smiley face sticker.

KEY TAKEAWAYS ⚡

Standard manhole opening: 26" × 22" (rectangular) or 26" diameter (round)—no exceptions for "I skipped breakfast"
Smaller 24" opening allowed ONLY for:
- Low-voltage/limited energy circuits (fiber, Class 2/3/4, fire alarm)
- Must have a fixed ladder that doesn't block escape
- If there's REAL POWER, use the BIG hole
Keep the opening clear of anything that'll injure you or block emergency egress
Don't put the opening directly above energized equipment unless you add a barrier or fixed ladder
Covers must be 100+ lbs or tool-required to open—and designed so they can't fall in
Mark the cover clearly so everyone knows it's electrical

REAL-WORLD SCENARIOS 🔧

Scenario 1: The Retrofit Nightmare

You're upgrading an old manhole that currently has a 22" round cover—because apparently in 1957, electricians were smaller or more flexible. You're adding a new 480V feeder.

The Problem: That undersized opening might've been grandfathered, but the minute you alter the installation, you're bringing it up to current code.

The Fix: You need to enlarge that opening to at least 26" diameter. Yeah, it means cutting concrete and a new frame. No, you can't "just squeeze through it." The inspector won't squeeze through it either, and he's the one with the red tag.

Scenario 2: The Fiber Guy's Folly

A low-voltage contractor installed a new manhole for fiber optic runs and used a 24" opening—totally legal under the exception. NOW your GC wants you to run a 208V circuit through the same manhole for some pad-mount equipment.

The Problem: The second you add power circuits, you lose the exception. That 24" opening is no longer code-compliant.

The Fix: Either enlarge the opening to 26" or run your power somewhere else. "It was legal when we installed it" doesn't cut it when you're changing the use.

Scenario 3: The Ladder-to-Nowhere

You're inspecting a manhole that has the opening directly above a 15kV switch. There's no ladder, no barrier, nothing—just a straight 8-foot drop onto instant death.

The Problem: Violates 110.75(C) in the worst possible way.

The Fix: Install either a protective barrier over the equipment OR a fixed ladder that guides you down away from the energized gear. Preferably the ladder—at least then you're not trying to climb over a barrier in an emergency.

Scenario 4: The Disappearing Cover

Someone installed a lightweight aluminum manhole cover because "it's easier for the guys to move." Great, except now it's light enough that it blew off during a storm, and some kid almost fell in.

The Problem: Cover doesn't meet the 100-lb minimum and wasn't designed to require tools.

The Fix: Replace it with a proper cast iron cover that weighs enough to stay put, or use a bolted/locked design. Code isn't being difficult here—it's keeping people alive.

WHAT TO STUDY 📚

Exam-Favorite Topics:

The actual dimensions - 26" × 22" rectangular, 26" diameter round. They LOVE asking this.
The 24" exception - Know that it's ONLY for low-voltage/limited energy circuits AND requires a fixed ladder. Mixing power circuits in there? No dice.
Cover weight requirement - 100 pounds minimum OR tool-required opening. Expect a question about why this matters.
Location relative to equipment - You'll get a diagram showing a manhole with the opening over a transformer. You need to identify that it requires a barrier or ladder.
What makes an opening "obstructed" - They might show you a photo or drawing with a conduit elbow right in the egress path.

Calculation Alert:

None really, but you might need to convert between inches and millimeters. Know that 26" ≈ 650mm and 24" = 600mm.

Common Trick Questions:

"Can you use a 24" opening for a manhole with 120V circuits and fiber?" NO. Power circuits kill the exception.
"Does a 95-pound cover meet code if it requires a special wrench to open?" YES. It's under 100 lbs BUT requires tools, which satisfies the requirement.
"Can the cover protrude 2 inches into the manhole?" ONLY if those 2 inches can't possibly contact conductors or equipment. Generally, don't let it protrude at all.

The Bottom Line

This section exists because people have been injured, trapped, and killed in manholes over the years. The Code is trying to make sure:

You can actually fit in and out (preferably quickly if things go wrong)
You're not landing on energized parts
Random people aren't opening it for fun
Everyone knows it's an electrical vault

It's not complicated, but it IS life-safety critical. Build it right, and everyone goes home with the same number of limbs they started with.

Remember: If you can't comfortably escape from a manhole in 10 seconds while wearing your gear, it's not built to code—or common sense.

Now get back to work, and quit eating so many donuts so you fit through that 26" hole! 😂

Stay safe down there, sparky. The Code's got your back...and your egress route.