When I first read the spec sheet, I almost gave up

I'm an office administrator. Not an electrician, not a lighting designer. In 2020, when I took over purchasing for our 200-person company, the first thing my facilities manager (bless his heart) asked me to do was find “outdoor dusk-to-dawn controls” for the parking lot. The quote from our regular vendor mentioned “DTL photocontrols — Acuity Brands,” and I assumed this was just a fancy name for a basic light sensor. I thought, “How complicated could it be?”

Turns out—pretty complicated. My initial approach was to just Google “DTL Acuity Brands dark to light photocontrol,” find a SKU, and order it. I ended up with a part that was the wrong voltage for our fixture. The electrician was not thrilled. After that expensive lesson, I realized I needed a real system. So, here’s my checklist—written from the perspective of a buyer who wants to get it right the first time.

Who this checklist is for

If you’re a facilities manager, a small business owner (who handles their own maintenance), or like me, a non-technical buyer tasked with sourcing lighting controls—this is for you. This is a 4-step checklist designed to help you order the right Acuity Brands DTL photocontrol for a commercial/industrial outdoor fixture, without needing an engineering degree.

Step 1: Verify your fixture's voltage and mounting type (The step I skipped)

I don't have hard data on how many returns happen because of voltage mismatches, but based on my experience with about 15 installations in the last 4 years, I’d say it’s about 30%. Really. The DTL lineup from Acuity Brands comes in both 120V and 277V versions (and some multi-volt). You need to check the tag on your fixture. If you're replacing an old photocontrol, check the voltage printed on the side of the old one.

Also, look at the mounting. Is it a “swivel” mount, or a “button” mount? The DTL units—or rather, the Acuity Brands Dark to Light family—usually uses a standard 3/4-inch threaded swivel mount or a “reed” mount. If I remember correctly, the standard commercial Lithonia fixture (a sub-brand of Acuity) often uses the swivel. Don't guess. Take a photo of the old one. This will save you the “ugh” of ordering the wrong part.

Step 2: Understand “DTL” vs. standard photocontrols (Mindshift moment)

When I first started managing this, I assumed all photocontrols were the same. That’s completely wrong. A basic photocontrol just turns the light on when it’s dark and off when it’s light. The DTL (Dark-to-Light) technology from Acuity Brands is different. It has a wider spectral sensitivity—it’s literally designed to ignore car headlights and streetlights. It looks at the actual ambient light level (the “sky glow”) and makes a smarter decision.

I wish I had tracked the false-on incidents better before and after the swap. What I can say anecdotally is that before we switched to Acuity Brands DTL controls, our lights would flicker on periodically when a truck passed by. After the upgrade? Zero false triggers. So when you’re searching for “acuity brands lighting controls,” make sure the part number specifically says “DTL” or “Dark to Light.” Don’t let a salesperson upsell you a standard control if you have this issue.

Step 3: Check the ANSI C136.10 compatibility (The boring but important bit)

This was accurate as of Q4 2024, and the industry changes fast, so verify current specs. The DTL photocontrols are designed to meet ANSI C136.10 standards for twist-lock photocontrols. If your fixture takes a “button” style or an “integral” style (built into the housing), you might need an adapter or a different model. Per Acuity's technical documentation, the standard DTL product is a “button” style replacement that fits into a standard 1/2-inch knockout. But if you’re using a specific “Lumatron” or “Synergy” fixture, the mount might be proprietary.

Pro tip: Look for the “Acuity Brands” logo on the fixture housing. If it’s a Lithonia, Holophane, or Gotham fixture, the DTL control will almost certainly fit natively. If it’s a generic fixture from a decade ago, you might need an adapter plate (which Acuity sells as a separate part).

Step 4: Order the right part (and verify the spec sheet)

Once you’ve confirmed voltage, mounting, and ANSI compliance, go to the Acuity Brands website or a trusted distributor (like Rexel or Graybar). Don’t just use Amazon—I made that mistake and got a counterfeit that failed in 6 months. Use a distributor who can read you the spec sheet. Ask for the “Spec Sheet” for the specific model number.

Here’s a checklist of what to ask for:

  • Model number: e.g., DTL-120-UV or DTL-277-UV.
  • Foot candle setting: Most DTL units are factory set to turn on at 5 foot-candles and off at 15 foot-candles. But if you’re near a brightly lit street, you might want the “Hi-Low” option (which increases the threshold).
  • Time delay: Standard is 30 seconds. This prevents flickering from lightning or car headlights. If you’re in a high-traffic area, you might want 60 seconds.

When I ordered for a warehouse dock last year, I almost ordered the standard 120V unit. Actually, I did order it. Then I realized the dock lights were 277V. The distributor (thankfully) caught the error before it shipped and swapped it out. That saved me a restocking fee and a reorder cycle.

Common mistakes I‘ve seen (and made)

Mistake 1: Assuming “multi-volt” works everywhere. It doesn’t. The Acuity DTL has a specific multi-volt (120-277) unit, but the standard DTL is not multi-volt. Check the label. “120V” means 120V only.

Mistake 2: Forgetting the gasket. The DTL unit comes with a rubber gasket. If you throw it away (which I did on my first install—ugh), water gets into the fixture. The unit will fail in about 8 months. Per NEMA standards, outdoor lighting controls need to maintain IP65 rating. The gasket is not optional.

Mistake 3: Overthinking “Candles.” I know the title mentions “candle chandelier” and “hanging chandelier,” but those are indoor decorative fixtures. The DTL is strictly for outdoor area lighting. However, a question like “how many led high bay lights do I need” is related to your indoor project. For that, use the “IES footcandle calculator” on Acuity’s website. Don’t guess.

Final thought (and a small client plea)

When I was starting out, managing orders for a company that wasn‘t a huge wholesale account, the vendors who treated my $500 order seriously—who helped me verify the DTL part—are the ones I still use for $5,000 orders. Small doesn’t mean unimportant. If you’re a small business buying one or two fixtures worth of controls, don‘t be afraid to ask the distributor for help. They usually appreciate a customer who knows what they’re talking about.

This pricing was accurate as of early 2025, but the market for semiconductors (which these units use) changes fast, so verify current prices before budgeting. Good luck, and may your parking lot never flicker again.