Posted by Doug Root on 16th Oct 2019

How to Choose Which LED Corn Cob Retrofit Bulb is Right for Replacing Your Metal Halide or High Pressure Sodium Bulbs

We Can Help You Replace Metal Halide lamps with LED Corn Cobs. We're Professionals!

Image of a corn cob LED light next to an ear of corn

Corn Cob LED lights are a truly great invention. You can't eat them, but you can light them! They are a wonderful replacement for the technologies of the past, such as metal halide and mercury vapor.

Why Are They Called Corn Cob lights?

Higher wattage  LED replacement bulbs are referred to as corn lights because the rows of LED chips on the lamp look similar to the rows of cob on an ear of corn!

LED corn cob lights are one of the most efficient ways to replace  metal halidemercury vapor, and high-pressure sodium HID bulbs.

LED corn cob lamps come in 2 basic types - Direct Wire (ballast bypass) or Ballast Driven (plug-and-play). For today's blog, we’re going to focus on the ballast bypass lamps and why you should  consider switching from metal halide to LED corn cob lights.

Direct Wire / Ballast Bypass

Direct wire or ballast bypass LED corn cob lights operate directly on line voltage. We have found over the years that most of our customers prefer to replace their metal halide lamps with Direct Wire (ballast bypass) versions. Most like the idea of removing the transformer (ballast) and running line voltage directly to the medium household base (E26) or mogul base (EX39/E39) socket. This will reduce power usage and maintenance as you will be removing the power consumed by the ballast and the need to replace that ballast in the future.

Auto Voltage Sensing

Most of the corn cob LED lights on the market are auto voltage sensing. They can operate on a range between 120 and 277V. So if the operating voltage of your circuit is 120V, 208V, 220-240V or 277V, any of the "120V-277V" rated lamps will work. Corn cob lights come in a range of lumen outputs, replacement wattages start as low as 12 watts and go as high as 200 watts. These corn cobs can replace a 50W metal halide up to a 1000W metal halide.

Color Choices

The  color choices are fantastic with LED corn cobs. Color ranges for most brands like Keystone Lighting Technologies, Philips, Arva & Halco begin at 3000K and go up to 5000K. The warmer 3000K light is a great way to simulate 3000K metal halide lamps like the Philips MHC100/U/M/3K or ALL high-pressure sodium lights. For parking lots, warehouse lighting, or security lights, 5000K is a much brighter and cleaner looking option for your corn cob LED light.

Common metal halide to LED replacements:

50W Metal Halide Replacement for MH50/U/MED, MVR50/U/MED, MXR50/U/MED

70W Metal Halide Replacement for MH70/U/MED, MH70W/U/PS, MVR70/U/MED, MXR70/U/MED/O MH50/U/M/4K, MP50/U/MED

100W Metal Halide Replacement for MH100/U/MED, MVR100/U/MED, MHC100/U/M/4K, MH100W/U/PS, MP100/U/MED, MXR100/U/MED/O

150W Metal Halide Replacement for MH150/U/MED, MVR150/U/MED, MHC150/U/M/4K, MH150W/U/PS, MP150/U/MED, MXR150/U/MED

175W Metal Halide Replacement for medium and mogul base MH175/U/MED, MVR175/U/MED, MH175W/U/MED, MP175/U/MED, MVR175/U, MH175/U, M175/U, H39JA-175DX

250W Metal Halide Replacement MH250/U, MVR250/U, M250/U, M250/U/BT28, H37KC-250DX

400W Metal Halide Replacement MH400/U, MH400/BU, MP400/BU, MVR400/U, H33GL-400DX

1000W Metal Halide Replacement MH1000/U, MVR1000/U, M1000/U

PROS and CONS of Corn Cob LED Retrofit Lights


  • Fantastic Return On Investment - Usually, our customers can see a return on investment (ROI) within 6 months. This typically depends on your electricity rate and the cost to install the lamps.
  • Life - The lifespan of a typical corn cob LED light is 50,000 hours which is almost double the life of most metal halide lamps, and the lumen depreciation is much better. At 50,000 hours, these lamps will retain 80% of the light output they had when new. Metal Halide lumen depreciation is typically at 50-60% at the end of life.
  • Energy Savings - You can usually cut your power usage in half, if not more.


  • Size Matters - One of the main issues our customers seem to face is that the LED replacement corn cob light is too large to work in their fixture. The reason being is that to pack a punch of 10,000 + lumens, you need a lot of surface area to put the LED chips onto. As a result, some of the LED replacements are larger than their metal halide counterparts. Be sure to measure your space and verify the corn cob will fit.
  • Heat kills LEDs - When an LED is placed into operation in a fully enclosed fixture, you run the risk of some life deterioration. Death of the LED corn cob can be premature due to heat build-up. This is why we always suggest using higher-tier manufacturers. The lower-cost manufacturers use inferior components that may fail, and who knows if they will be around or not if you need to use your warranty.
  • Surges - Corn cob LED lights are typically used in industrial and commercial applications where surges in line voltage can happen. Lightning strikes or voltage irregularities can burn up your LED investment. Most LED corn cobs come with a 5KV or 8KV surge suppressor built into the base of the lamp. Make sure to check the surge suppression when shopping and remember that you can always add a surge suppressor in line to help protect your investment.

Call Us Now

If you need any help choosing the LED corn cob that is right for you or with switching from metal halide to LED lights, please  give us a call or use the live chat button on our site. Let's talk!