Product Overview
Potter & Brumfield KRP-3DH-12 DPDT Power Relay, 12VDC Coil, 8-Pin Octal Plug-In
Condition
Unused new old stock, clean and in excellent condition. The clear polycarbonate case is bright with no cracks or hazing, and the armature, contact stacks and coil are fully visible through it. The octal pins are straight, bright and free of corrosion or solder, and the black base is unmarked by socket wear. Orange ink marks from the factory are visible on the case side and on an internal insulator strip. The case is printed P&B tyco, KRP-3DH-12, 3/4HP 20A 1PH, 115VAC 240VAC, COIL:12VDC, MADE IN MEXICO, with a UL mark and the contact schematic.
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Product Overview
The KRP-3DH-12 is a general purpose plug-in power relay from the long-running Potter & Brumfield KRP family, carried forward under the Tyco name and marked with both on the case. A 12VDC coil pulls in two contact sets that the case rates at 20A, 115VAC and 240VAC, 3/4HP single phase. The schematic printed on the face draws those two sets side by side, each with one moving blade and two fixed contacts, worked by the single coil below - a double-pole double-throw arrangement, two Form C - and the base backs it up: a standard 8-pin octal pattern, two pins for the coil and three for each pole, numbered 1 through 8 around a keyed center post so orientation is unmistakable. The clear case is the practical part of the design, and always was: you can watch the armature pull in without lifting the relay out of its socket.
Key Features
- Manufacturer marking: P&B tyco (Potter & Brumfield)
- Part number: KRP-3DH-12
- Coil: 12VDC, printed on the case
- Contact arrangement: DPDT, double-pole double-throw (2 Form C), per the schematic printed on the case and the 8-pin octal base
- Contact rating printed on the case: 20A, 115VAC and 240VAC
- Motor rating printed on the case: 3/4HP, 1PH
- Base: 8-pin octal plug-in, pins numbered 1 through 8, keyed center post
- Case: clear polycarbonate dust cover over the mechanism
- UL mark and contact schematic printed on the case
- Country of manufacture: Made in Mexico, per the case marking
- Condition: unused new old stock, one piece in stock
Applications
- Maintenance electrician replacing a failed plug-in relay in a legacy machine tool control panel wired for 12VDC control
- Panel builder needing a socketed DPDT relay to switch 115VAC or 240VAC loads from a 12VDC logic or battery-backed control circuit
- Equipment restorer bringing an older piece of industrial gear back to its original socketed relay rather than adapting a modern footprint
- Bench technician who wants a clear-case relay so contact and armature action can be watched while troubleshooting a control sequence
Frequently Asked Questions
What contact arrangement is this?
DPDT - two poles, each with a common and both a normally open and a normally closed contact, which is two Form C sets. That comes straight off the part: the schematic printed on the case shows the two changeover sets driven by one coil, and the 8-pin octal base carries exactly the right count, two coil pins plus three pins per pole. Wire it to the pin numbers molded into the base and check them against your socket before you commit it to a panel.
What coil voltage does this relay use?
The case is printed COIL:12VDC, so it is a 12 volt DC coil. That marking is what the part carries and what we can confirm; we do not state a coil resistance or pull-in current because neither is printed on this piece.
How much load can the contacts carry?
The case markings read 3/4HP, 20A, 1PH, 115VAC and 240VAC. Those are the ratings printed on this relay. It has not been electrically tested here, so treat the case markings as the specification and derate for your own duty cycle and inrush.
Does it come with a socket or hold-down clip?
No. What ships is the relay itself, the piece in these photographs. Any octal socket, retaining clip or DIN rail hardware you need is separate.
What am I actually getting, and what am I taking on?
You are getting the exact relay in these five photographs: one KRP-3DH-12, unused new old stock, clear case bright, octal pins straight and free of solder or socket scuffing, orange factory ink still on the insulator strip. What you are taking on is that nothing electrical has been done to it here - no coil supply, no pull-in test, no contact resistance check. The case markings are the specification and the photographs are the spec for this piece, right down to the printed schematic you can read for yourself. If the job needs a documented test report, buy new. If you need a known, marked, correctly configured KRP for a socket that has been empty since the last shutdown, this is one identified relay listed on its own rather than buried in a pallet of unknown coil voltages. This item clears our free-shipping line on its own, and it leaves the Idaho warehouse the same or next business day.
A clear case was never decoration - it let an electrician on a ladder see the armature pull in without touching a thing. Drop this one into its socket and it goes straight back to that quiet, visible work for whoever is watching next.
