Product Overview
Empro HA-5-50 Bolt-Mount Current Shunt, 5 Amp 50 Millivolt Output, Four Terminal Brass Construction
Condition
Used, inspected, and in excellent condition per our evaluation. Clean with normal handling signs from prior installation, and fully functional with no performance concerns. The photos show a molded black insulating base with two mounting ears, two solid brass current blocks carried on zinc-plated hex bolts, and smaller brass potential screws set inboard of them. One brass block is stamped HA 5 50 directly into the metal; the opposite block carries a shallow stamped maker cartouche with a two-terminal shunt symbol whose lettering is too faint to read in the photo. The white front label reads 5 AMP 50 mV Shunt. A few small dark specks are visible on the brass faces and there are fine swirl marks on the black center cover plate, both consistent with the used, clean grade above. The underside is clean, with brass slotted screws and metal mounting bushings intact.
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Product Overview
The Empro HA-5-50, also written HA550, is a precision current shunt rated 5 amps with a 50 millivolt drop at rated current, which works out to a nominal 0.01 ohm. Current enters and leaves through the two heavy brass blocks and their zinc-plated hex bolts; the two smaller brass screws inboard of them are the potential taps, so the meter reads the voltage across the resistive element rather than across your cable lugs. That four-terminal arrangement is why a shunt like this keeps its calibration when a plain resistor would not. The resistive element sits under the black cover plate between the blocks, and the whole assembly is mounted on a molded insulating base with two through-hole ears for panel or standoff mounting. Accuracy class and temperature coefficient are not marked on the unit and are not confirmed - verify against the Empro datasheet or against a known reference before use in a calibrated setup.
Key Features
- Brand: Empro
- Model: HA-5-50, stamped HA 5 50 into the brass block
- Current rating: 5 A
- Output: 50 mV at rated current
- Nominal resistance: 0.01 ohm, derived from 50 mV at 5 A
- Four-terminal construction: two brass current blocks with hex bolts plus two brass potential screws
- Molded black insulating base with two mounting ears and metal-bushed through holes
- Front label reads: 5 AMP 50 mV Shunt
- Accuracy class and temperature coefficient: not confirmed, verify against the datasheet before use
Applications
- Calibration technician setting up a 5 A DC current reference on the bench and needing a stable millivolt drop to feed a precision DVM
- Instrumentation engineer driving a 50 mV full-scale analog panel meter or a millivolt input data logger from a DC line
- Battery lab tech logging charge and discharge current on a low-current pack without inserting a lossy sense resistor in the wire
- Restorer rebuilding a vintage test panel or power supply that was built around a standard 50 mV shunt and needs the original interface
Frequently Asked Questions
What resistance does 5 A at 50 mV work out to?
50 millivolts across 5 amps is a nominal 0.01 ohm, or 10 milliohms. That is the design value implied by the rating; the accuracy class is not marked on this unit, so check it against a known reference if your measurement needs a tolerance figure.
Does this shunt have separate sense terminals?
Yes. The two large zinc-plated hex bolts on the brass blocks are the current terminals, and the two smaller brass screws set inboard of them are the potential taps for your meter leads. Wire the load current to the big bolts and the meter to the small screws so lug and cable resistance stays out of your reading.
What part number should I search for?
The brass block is stamped HA 5 50. The same part appears written as HA-5-50 and HA550 in catalogs and in older equipment documentation. All three refer to this 5 A, 50 mV Empro shunt.
What exactly is included?
One Empro HA-5-50 shunt as pictured, with its terminal bolts in place. The two loose zinc-plated bolts and nuts sitting beside the shunt in the first photo are not confirmed as part of the sale, so ask us before ordering if you are counting on extra hardware.
Why buy a single shunt here instead of a multi-pack somewhere else?
Because a bench usually needs one shunt, not five. We stock one of these and we will sell you exactly that, instead of forcing a lot of 10 or 50 you will never use. Shipping is $8 flat rate and free over $28, and orders leave our Idaho warehouse the same or next business day.
A shunt is the quiet broker in a current measurement: it never reads the number, it just makes the number honest. Bolt this stamped HA 5 50 into your panel and let five amps turn into a clean fifty millivolts on your meter.
