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Streetlight Isolation Transformers
Stop stray voltage on metal poles. A hermetically sealed toroidal 120/120 V isolation transformer in a waterproof red housing - built for streetlights, traffic signals, parking lots, and other public poles.
Stray Voltage Stops at the Pole
Streetlight isolation transformers break the earth-return path at the pole so a failed hot or neutral cannot put hazardous voltage on a metal streetlight, traffic signal, or parking-lot pole. Galvanic isolation at the base restores a safe condition without pulling a new equipment ground through the feeder.
Developed for municipal stray-voltage programs – including thousands of units placed in New York City – every unit is designed and manufactured in Shelton, Connecticut, with standard 1200, 2200, and 8000 VA ratings and custom voltages on request.
A high-efficiency toroidal core is potted in black epoxy inside a red resin housing: 100% waterproof, center-bolt mounted, with a carrying handle and an internal auto-reset thermal protector. 120/120 V is standard; 50 Hz and other voltages are available.
Use them on streetlights, traffic signals, parking lots, sports complexes, marinas, and any other line-powered metal pole where public contact is possible and a wiring fault cannot be allowed to energize the structure.
Streetlight Isolation Transformer Specifications
Standard streetlight isolation transformers are 120/120 V toroidal units in a hermetically sealed red housing. Choose 1200 VA, 2200 VA, or 8000 VA rating.
| Model | Power | Input / Output | Frequency | Protection | Housing | Mounting | Environment |
|---|---|---|---|---|---|---|---|
| SLT-1200 | 1200 VA | 120 / 120 V | 50 / 60 Hz | Auto-reset thermal | Red resin, black epoxy potting | Center bolt + handle | 100% waterproof |
| SLT-2200 | 2200 VA | 120 / 120 V | 50 / 60 Hz | Auto-reset thermal | Red resin, black epoxy potting | Center bolt + handle | 100% waterproof |
| SLT-8000 | 8000 VA | 120 / 120 V | 50 / 60 Hz | Auto-reset thermal | Red resin, black epoxy potting | Center bolt + handle | 100% waterproof |
| Custom | As specified | As specified | 50 / 60 Hz | Auto-reset thermal | Red resin, black epoxy potting | Center bolt + handle | 100% waterproof |
SLT-1200 (1200 VA): 7.75″ OD × 3.75″ H (196 × 96 mm), 16 lb (7.2 kg). Dimensions for 2200 VA and 8000 VA available on request.
Custom ratings
Need a voltage other than 120/120 V, a 50 Hz unit, or a power rating between or above the standard 1200, 2200, and 8000 VA models? We build custom streetlight isolation transformers to the circuit.
The Streetlight Isolation Transformer was engineered for US utilities - light & hermetically sealed red housing, toroidal galvanic isolation, waterproof pole-base duty and auto-reset thermal protection - built for metal poles, for public safety
Hermetically sealed for pole-base duty
Black-epoxy potting inside a red resin housing makes the unit 100% waterproof for streetlight bases, handholes, and outdoor pedestals.
Toroidal isolation, not a 12 V lighting driver
This is a 120/120 V galvanic isolation transformer – it separates the pole circuit from the utility secondary so a wiring fault cannot energize the metal pole.
Built to stop stray voltage
Wear, water, and aging insulation can put hazardous voltage on a pole; isolation removes the earth-return path that shocks people and animals.
Proven in municipal service
The design was developed for New York City streetlights and has thousands of units in the field.
Made in the USA, built to spec
Designed and manufactured in Shelton, Connecticut, with custom VA and voltage options when a standard 1200, 2200, or 8000 VA unit is not the right fit.
When a Metal Pole Goes Live, Don't Leave the Public Unprotected
An insulation failure inside a metal pole – from water in the base, aging wiring, damage, or a lost equipment ground – can put stray voltage on the pole even when the streetlight still works. Anyone who touches it can be shocked. Finding and rewiring the feeder often takes days.
Streetlight isolation transformers solve this by connecting at the pole base between the utility secondary and the fixture circuit. The toroidal 120/120 V unit provides galvanic isolation: there is no copper path from line to the pole circuit, so a failed hot or neutral inside the pole has no earth-return through a person.
The hermetically sealed red housing sits in the wet base, with center-bolt mounting and an auto-reset thermal protector. The light stays on the isolated secondary while crews schedule the permanent repair – stray voltage stops at the pole.
Utility Lighting Isolation Transformers
Streetlight isolation transformers – developed for municipal stray-voltage programs, engineered and built in Shelton, Connecticut.
Frequently Asked Questions
What is a streetlight isolation transformer?
A streetlight isolation transformer is a 120/120 V toroidal isolation transformer that sits at the pole and electrically separates the fixture circuit from the utility secondary. Bridgeport Magnetics units are hermetically sealed in a red resin housing, potted in black epoxy, and built to stop stray voltage on metal streetlight, traffic-signal, and parking-lot poles.
How does a streetlight isolation transformer stop stray voltage?
Stray voltage appears when a failed hot or neutral inside the pole uses the metal pole – and then a person or animal – as a path to earth. Galvanic isolation removes that path. Power crosses the toroidal core magnetically, with no copper connection from the utility feed to the pole circuit, so a wiring fault cannot energize the pole.
Is this the same as a landscape lighting transformer?
No. A landscape lighting transformer steps 120 V down to 12 V or 15 V for low-voltage fixtures. This product is a 1:1 streetlight isolation transformer. It does not change voltage. It isolates the pole circuit so stray voltage cannot appear on the metal structure.
Will it still work after an LED streetlight retrofit?
Yes. LED heads use less wattage than HID, but they do not fix water in the base, failed insulation, or a missing equipment ground. Isolation is a safety function, not a lamp driver. Size the unit to the actual fixture load – 1200 VA, 2200 VA, or 8000 VA – and the isolated secondary will feed the LED head the same way it fed the old lamp.
What sizes are available?
Standard ratings are 1200 VA, 2200 VA, and 8000 VA at 120/120 V, 50/60 Hz. Each includes an auto-reset thermal protector. The 1200 VA unit is 7.75″ OD × 3.75″ H and weighs 16 lb. Other voltages and ratings are built to the circuit.
Where is a streetlight isolation transformer installed?
It installs at the pole base or in the service handhole, between the utility secondary and the fixture wiring. The red housing mounts with a single center bolt and includes a carrying handle. Typical sites are metal-pole streetlights, traffic signals, parking lots, sports complexes, marinas, and other line-powered poles in public areas.
Is the red housing waterproof?
Yes. The toroidal transformer is embedded in black epoxy inside a red resin container. The assembly is 100% waterproof for wet pole bases and outdoor pedestals. An internal auto-reset thermal switch opens on overload and resets when the unit cools.
Can you build a custom streetlight isolation transformer?
Yes. Standard units are 120/120 V at 1200, 2200, or 8000 VA. Custom designs cover other voltages, 50 Hz, and ratings between or above the standard models. All units are engineered and manufactured in Shelton, Connecticut.
