How to Read a Switchgear Nameplate

Bus amperage

The bus rating is the continuous current the lineup is built to carry, and it is the first thing any buyer looks for. Standard steps such as 800A, 1200A, 2000A, 3000A and 4000A resell fastest, because they match what facilities actually specify. An unusual rating is not a problem, but it narrows the resale pool.

Note that the main breaker rating and the bus rating are often different numbers, and the bus rating is the one that matters most for resale. A 3000A bus with a 2000A main is still a 3000A lineup to the next owner.

Voltage class

Voltage is what divides the market. Low voltage gear at 208V, 240V and 480V is the volume market and sells steadily. Medium voltage at 5kV, 15kV, 27kV and 38kV is a smaller market with much higher individual values and long new-build lead times, which is why serviceable medium voltage lineups are among the most valuable equipment we buy.

The plate usually shows a maximum design voltage alongside the nominal system voltage. 15kV class gear, for instance, is often marked 15kV with a 15.5kV or 17kV maximum. Both numbers are useful, so photograph the whole plate rather than one line.

Short circuit and interrupting ratings

The withstand or interrupting rating, quoted in kA, tells the next owner what fault current the gear can survive. This matters more than sellers realise: a lineup with a high interrupting rating fits more installations, so it resells faster and for more.

On medium voltage gear you may see both a symmetrical interrupting rating and a momentary rating. Capture both if they are shown.

Type designation and shop order

The type designation is the manufacturer's model family, and it is how the resale market actually searches. Names like QED, Magnum DS, Power Break, Pow-R-Line, Spectra, AKD, DS, DSII, Centerline and Vista carry immediate meaning to a buyer.

The shop order or general order number lets the manufacturer retrieve the original drawings for that specific lineup. That is genuinely valuable to the next owner, so it is worth photographing even though it looks like an internal reference.

Bus material: the field that changes the number most

The plate may state whether the bus is copper or aluminum, and if it does not, the drawings usually will. Copper bus commands a meaningful premium over aluminum at every amperage and voltage class, both because it is worth more as metal and because a large part of the resale market specifies copper only.

If you cannot determine bus material from the plate, say so rather than guessing. We can usually tell from the type designation and the vintage, and if it is genuinely ambiguous we confirm it at inspection rather than pricing it down.

Enclosure type and what it implies

NEMA 1 means indoor, and indoor gear that never saw weather is the cleanest thing we buy. NEMA 3R and 4X indicate outdoor construction, which is a different market: outdoor lineups and walk-in switchhouses are heavier, more expensive to freight, and their value depends heavily on how well the enclosure resisted corrosion.

If your gear is outdoor, photograph the roof, the door gaskets and the base channel. That is where weather damage shows first, and being upfront about it produces a firmer offer that will not be re-traded on arrival.