Matching pair of vintage General Electric Time Overcurrent Relays model 121AC51B4A used in industrial electrical protection and power distribution systems. These heavy-duty electromechanical relays were commonly installed in utility infrastructure, pump stations, water systems, substations, and industrial feeder protection applications during the mid-20th century. Featuring exposed analog mechanisms, adjustment dials, original utility/service tags, and classic GE industrial engineering construction.
SEO SNIPPET:
General Electric time overcurrent relay GE 121AC51B4A protective relay industrial electrical relay vintage utility equipment electromechanical relay power distribution relay substation equipment pump feeder relay Kennebec Water industrial control steampunk electrical engineering surplus equipment analog industrial decor
Love the item but not the price? Send an offer — industrial surplus and vintage utility equipment buyers know how difficult matching GE relay sets are becoming to find, especially in clean condition with original tags and intact internals.
This listing is for:
(2) Matching General Electric Time Overcurrent Relays
Model:
121AC51B4A
These are authentic vintage industrial protective relays used in electrical distribution and feeder protection systems. One relay still retains a handwritten service/application tag referencing “Kennebec Water” and “Pump Feeder,” adding real-world utility provenance and display appeal.
The exposed electromechanical internals, analog adjustment mechanisms, copper coil assemblies, and heavy industrial housings give these an incredible Cold War era engineering aesthetic.
Condition Description:
Untested vintage industrial surplus equipment being sold for parts, repair, restoration, display, or collector use. Both units appear exceptionally clean internally with intact components, adjustment dials, coils, housings, and viewing windows. No obvious burn damage, melted wiring, or major corrosion was observed during visual inspection.
One relay still retains its original handwritten industrial/service identification tag referencing “Kennebec Water” and “Pump Feeder,” adding utility provenance and display appeal.
These relays may potentially function properly, however no operational or electrical testing has been performed. Due to the specialized nature of industrial electrical equipment, both units are being sold strictly as untested surplus in parts or repair condition.
Known Markings:
GENERAL ELECTRIC
TIME OVERCURRENT RELAY
MODEL 121AC51B4A
GEH-1265
Made in U.S.A.
Electrical Ratings:
Inverse Time:
4–16 Amperes
Instantaneous Unit:
20–80 Amperes
60 Cycles
These are excellent for:
Industrial collections
Electrical engineering displays
Utility memorabilia
Steampunk décor
Surplus restoration
Power systems collectors
Analog industrial display
Vintage lab/engineering aesthetic
The visual appeal on these is exceptional with exposed mechanisms, bakelite style construction, copper coils, industrial dial adjustments, and original utility tags.
ITEM SPECIFICS
Brand
General Electric
Model
121AC51B4A
Type
Time Overcurrent Relay
Current Type
AC
Current Rating
4–16 Amp Inverse Time / 20–80 Amp Instantaneous
MPN
121AC51B4A
Number of Pins
Industrial Terminal Configuration
Application
Industrial, Utility, Electrical Distribution, Pump Feeder
Features
Electromechanical, Analog Adjustment Dial, Industrial Surplus, Utility Provenance
Material
Metal, Bakelite, Glass, Copper
Color
Black, Silver, Copper
Country/Region of Manufacture
United States
Vintage
Yes
Unit Quantity
2
Theme
Industrial, Utility Infrastructure, Engineering, Power Distribution, Steampunk, Cold War Era
Occasion
Display, Collection, Restoration, Industrial Use
CTA:
Vintage GE industrial protection equipment with exposed analog mechanisms has become increasingly desirable among electrical collectors, surplus buyers, utility historians, and steampunk/industrial décor enthusiasts. Matching pairs with intact internals and provenance tags are getting harder to source.
📦 SHIPPING INFORMATION
eBay automatically calculates the shipping cost using your location and the actual packed weight.
These items are heavy industrial electrical components and will require secure protective packaging.
Estimated packed weight:
18 – 28 lbs total combined
(Final weight is always updated at the time of packing.)
Estimated package dimensions:
18” x 14” x 12”
If the shipping looks higher than expected or is preventing checkout, you’re welcome to use the free USPS/UPS shipping calculator to confirm the rate.
We truly strive to keep shipping as fair and accurate as possible for heavy industrial equipment.
HASHTAGS:
#GeneralElectric #GERelay #IndustrialSurplus #ProtectiveRelay #TimeOvercurrentRelay #Electromechanical #VintageIndustrial #UtilityEquipment #PowerDistribution #ElectricalEngineering #Steampunk #IndustrialDecor #ColdWarIndustrial #AnalogEngineering #IndustrialControl #Substation #PumpFeeder #IndustrialElectronics #VintageGE #SurplusEquipment
LONG TAIL KEYWORDS:
General Electric 121AC51B4A relay, vintage GE protective relay, time overcurrent relay industrial, electromechanical utility relay, analog industrial electrical equipment, Kennebec Water relay, pump feeder relay, substation protection equipment, vintage power distribution relay, industrial surplus electromechanical control
STYLE / AESTHETIC KEYWORDS:
Industrial Core, Steampunk, Cold War Engineering, Analog Technology, Utility Infrastructure, Retro Engineering, Heavy Industrial, Mid Century Industrial, Laboratory Aesthetic, Power Plant Equipment
GOOGLE ALT TEXT:
Pair of vintage General Electric 121AC51B4A time overcurrent industrial relays with exposed electromechanical internals and utility tags
MARKETPLACE SEO:
GE relay, General Electric relay, industrial relay, protective relay, electrical surplus, utility equipment, industrial control equipment, analog relay, electromechanical relay, vintage industrial equipment
INVISIBLE 1PX SEO BLOCK:
General Electric 121AC51B4A time overcurrent relay vintage industrial utility electrical protection equipment electromechanical analog power distribution relay substation pump feeder Kennebec Water industrial surplus steampunk engineering display