Light Pole Anchor Bolt Replacement: What Size, How to Measure - Jarvis Lighting

Believe it or not, this is one of the most common problems contractors encounter in their projects.

The base plate of this new light pole does not match the bolt pattern of the anchor bolts in the concrete.

If you haven’t had this issue yet, there is a high probability that you will.

Light Pole Installation Base Light Pole Installation Base


Let me share with you how you can avoid this problem and make sure your light pole projects go smoothly and with no surprises. 

1. Get the Right Anchor Bolt Size.

If you are using an existing bolt pattern, you must make sure that the diameter of your anchor bolts meets the requirements of the light pole. 

Anchor Bolt Diameters

2. Understand Bolt Pattern, Bolt Circle and Bolt Square.

What is a “Bolt Pattern”?

A Bolt Pattern is the pattern of bolts on the light pole base.

You need to know the Bolt Pattern of the light pole in order to properly anchor your bolts in the base. 

So the pattern of your anchored bolts and the bolt pattern of your light poles have to match.

Otherwise, they will simply not fit or will be very unstable. 

Bolt Circle vs. Bolt Square

There are two main ways to measure the bolt pattern: Bolt Circle and Bolt Square

Bolt Circle bolt pattern for light poles

Bolt Circle

“Bolt Circle” - The most common and accurate method of measuring a bolt pattern. 

Measure from the center of one bolt and then in a diagonal pattern to the center of the next bolt.

Bolt Square bolt pattern for light poles

Bolt Square 

Measure from the center of the bolt to the center of the adjacent or next bolt along the edge of the square. 

You can also measure from the edge of one bolt to the edge of the next bolt for a bolt square measurement. 

You then divide that number by 0.707 which will convert it to a Bolt Circle.


3. Be on the same page with your team and suppliers.

Light Pole Bolt Patterns

When communicating with your suppliers or with your people on the job site, you want to make sure you are all on the same page on terminology.

For new construction, make sure to get the right template.

It might happen that your supplier will give you the wrong anchor pole template. 

While this is not your mistake, you still want to make sure and double-check with your supplier if the template they sent you is the correct one just for your peace of mind.

For replacement project, make sure to have the right measurements.

If someone gives you measurements or if you are providing the measurements, always clarify if you're talking about the bolt pattern measurements and specify which one, bolt circle or bolt square.  

By Kirby Corkill 0 comment


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