Robinson Engineering, Inc.

From the Box to the Panel: Building an Electrical Panel, Part 1

The experience of building an electrical panel can be very exciting and rewarding. If you’re fortunate enough to have this task as a part of your work, good for you! Not everyone can take a slab of metal, attach a bunch of components and wire it all together to make something that will actually function as it should and help a customer get a job done. A salute to you, Panel Builder!

If you’re new to the game, here’s a quick overview of getting components . . .

from the box           Electrical Components in Boxes             to the panel.            Electrical Panel

Next time we’ll talk about wiring, but for now we’ll just focus on panel layout.

Before you start, you need a plan to work off of. Usually such a plan is in the form of either an electrical drawing (schematic) or it could also be a wire chart. We’ll get into the details and benefits of each at a later date, but for now let’s just say you’re working with a schematic.

As a part of your schematic, you’ll hopefully have access to a graphical representation of how the panel should be laid out. A good place to start, then, is to place all components on the panel and mark holes that need to be drilled and tapped for you to mount whatever is going on the panel.

Control Panel Layout

Reminder: When figuring out the layout, be sure to consult the documentation found with each component and follow the manufacturer’s specifications for spacing and ventilation. Also, you should use a square to make sure that everything on the panel is lined up properly.

Electrical Panel Marked

Once you’re layout is planned, you’re ready to drill. As most customers would rather avoid extra holes in an electrical panel, be sure to drill accurately and use tapping oil or grease when you tap the holes to prevent breaking bits and other setbacks.

When the holes are all drilled and tapped, you’re ready to mount your components. Your panel probably look something like this:

Electrical Panel Layout

Or this:

Terminal Block

But not quite this yet:

Electrical Control Panel Wired

Congratulations on getting this far! What other steps do you take when laying out an electrical panel? Any advice for new panel builders?


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  1. Put 2″ wide masking tape on the back panel to start. Mark all your holes and drill and tap. Then remove the tape. This works on every panel except stainless. The tape is very hard to get off. The tape makes it easier to see the markings and if the panel is painted there is less chance of damaging the paint.

    • I’ve seen that done before, but never actually tried it. Thanks for the tip!

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