__
Temporary Power Restoration Products
At Bridgeport Magnetics Group, we help utility companies and linemen achieve fast temporary power restoration. Our PowerBack and Trident toroidal autotransformers deliver reliable balanced 120/240V service in minutes, with superior portability, efficiency, and rugged reliability for emergency outage response.
Temporary Power Restoration at the Meter in Minutes
Bridgeport Magnetics’ temporary power restoration autotransformers (PowerBack and Trident) regenerate a missing hot leg or neutral directly at the meter socket – restoring full balanced 120/240V or 120/208V service within minutes while permanent repairs are scheduled.
Designed by linemen, for linemen in collaboration with utilities, every PowerBack and Trident unit is manufactured in Shelton, Connecticut with a fast 1–2 week lead time. Built with high-efficiency toroidal cores, they include voltage and amperage monitoring plus redundant 2× trip overcurrent protection for safe, confident deployment in the field.
Our Customers
Power-Back & Trident Models
Compare ratings, enclosures, and features across the lineup.
| Trident | Powerback-Lite 15KVA | Powerback-Lite 20KVA | Powerback 15K-M | Powerback 20K-M | Powerback 30K-M | Powerback 50K-M | |
|---|---|---|---|---|---|---|---|
|
|
|
|
|
|
|
|
| High Efficiency Toroidal Auto Transformer | 20kVA (2x10kVA) | 15kVA | 20kVA | 15kVA | 20kVA | 30kVA | 50kVA |
| Recommended Service | 100A (one xfrm) 200A (two xfrm) | 150A | 200A | 150A | 200A | 320A | 400A |
| Circuit Breaker | 2x63A | 125A | 160A | 125A | 160A | 250A | 400A |
| Shunt Trip Temp. deg. C | NA | 105 | 105 | 105 | 105 | 105 | 105 |
| Corded Meter Adapter Included | 200A | 200A | 200A | 200A | 200A | 320A | AWG 1 cables with CAM-Lock Connectors + 9 Cables Hkit |
| Input/Output Voltmeters | Yes | Yes | Yes | Yes | Yes | Yes | NA |
| Integrated GFI with Defeat Switch | Optional | Optional | Optional | Optional | Optional | Optional | NA |
| GPS Tracking | Optional | Optional | Optional | Optional | Optional | Optional | Optional |
| Enclosure Type | Resin Case | Resin Case | Resin Case | NEMA 4 Stainless | NEMA 4 Stainless | NEMA 4 Stainless | NEMA 4 Yellow |
| Grounding | No Grounding Required | No Grounding Required | No Grounding Required | YES | YES | YES | YES |
| Dimensions (inches) | NA | 29 x 22 x 13 | 29 x 22 x 13 | 29 x 22 x 13 | 46 x 28 x 22 | 46 x 35 x 20 | 46 x 35 x 20 |
| Wheels (Diameter x Width) | NA | 10.5" x 3" | 10.5" x 3" | 10.5" x 3" | 10.5" x 3" | 12" x 4.5" | 12" x 4.5" |
| Weight (lbs.) | 46 + 38 | 91 | 110 | 120 | 140 | 220 | 290 |
A toroidal core makes Power-Back dramatically lighter than conventional E-I lamination units, so a single lineman can position it at the meter pan without a hoist or a second set of hands.
Connect at the meter in one turn. The Power-Back meter adapter installs fast and includes a neutral – so you restore service in minutes instead of running temporary above-ground conductors.
Airless tires designed for rugged deployments
A built-in 2× overcurrent trip safeguards the unit and the service during temporary restoration – safety engineered in, not bolted on.
Every Power-Back is Manufactured in Shelton, Connecticut, with a 1–2 week lead time. No import delays.
When a Single Leg Fails, Don't Leave Customers in the Dark
An open hot leg or neutral – caused by a storm, damaged underground cable, or equipment fault – can drop a customer’s service even when the upstream transformer is intact. Locating and repairing the fault often takes days.
Temporary power restoration autotransformers (also known as add-a-phase or service-saver devices) solve this by connecting between the meter socket and the meter to quickly regenerate the missing leg and restore full balanced 120/240V or 120/208V service.
PowerBack and Trident systems restore load current on an open hot leg up to their rated capacity and full service on an open neutral up to their neutral current rating – giving your crews the flexibility to schedule permanent repairs on their own timeline instead of working under emergency pressure.
When wheeling a cart isnt an option - rough terrain, flooded ground, easements, backyards - the Trident goes where a wheeled unit can't.
The first handheld modular toroidal restoration unit at <50lb weight – purpose-built with line crews and Unions with strict weight restrictions
~45 lb per transformer plus a 9 lb control unit. Built for easements, backyards, gravel, and flooded ground – restore service where wheeling is impossible.
A new weatherproof enclosure protects the unit through restoration in any conditions.
Connect at the meter in one turn. The Power-Back meter adapter installs fast and includes a neutral – so you restore service in minutes instead of running temporary above-ground conductors.
Every Trident is Manufactured in Shelton, Connecticut, with a 1–2 week lead time. No import delays.
Back online in days, not weeks.
Power-Back and Trident temporary power restoration autotransformers – developed hand-in-hand with utility line crews, engineered and built in Shelton, Connecticut.
Frequently Asked Questions
What is a temporary power restoration autotransformer?
A temporary power restoration autotransformer is a specialized secondary device – also known as an add-a-phase, Servisavor, or service-saver unit – that regenerates a missing hot leg or neutral on a single-phase service. It connects between the meter socket and the meter to quickly restore full 120/240V or 120/208V balanced power while the utility schedules permanent underground cable repairs. Bridgeport Magnetics’ PowerBack and Trident systems are leading examples of modern temporary power restoration solutions.
How does Power-Back connect to the service?
PowerBack temporary power restoration autotransformers install quickly using a single-turn meter adapter that includes a neutral. After isolating the fault per utility safety standards, a lineman removes the customer meter, attaches the adapter, reinstalls the meter, and energizes the unit. This process typically takes just minutes and eliminates the need for temporary above-ground conductors.
What's the difference between Power-Back and Trident?
PowerBack models are wheeled temporary power restoration units ideal for standard access sites like driveways and commercial lots. The Trident is a modular, hand-carried temporary power restoration system designed for difficult access – rough terrain, backyards, stairs, or flooded areas where wheeling isn’t possible. Both deliver high-efficiency toroidal performance and were developed with input from utility line crews.
Can Power-Back restore an open neutral as well as an open hot leg?
Yes. PowerBack temporary power restoration autotransformers restore load current on an open hot leg up to the unit’s rated capacity. On an open neutral, they restore full balanced service up to the neutral current rating. Note that the system cannot correct both a missing hot leg and neutral simultaneously on the same service.
Do the units include monitoring and safety protection?
Yes. All PowerBack and Trident temporary power restoration units feature built-in voltage and amperage monitoring so crews can verify restored service conditions in real time. They also include redundant 2× overcurrent trip protection and thermal safeguards for enhanced safety during temporary deployment.
Are these built in the USA, and what's the lead time?
Yes – every PowerBack and Trident temporary power restoration autotransformer is designed, wound, and assembled in Shelton, Connecticut. This domestic manufacturing provides reliable 1–2 week lead times with no import delays, helping utilities maintain strong fleet readiness.
Who uses temporary power restoration autotransformers?
Temporary power restoration autotransformers are primarily used by electric utilities, line crews, and contractors during storm recovery, underground cable faults, planned maintenance, and emergency outages. They are especially valuable for residential, multi-family, and light commercial services where fast restoration improves SAIDI/SAIFI metrics and customer satisfaction.
How long can a temporary power restoration unit stay connected?
Temporary power restoration units are designed for short-to-medium term use (typically days to a few weeks). Most utilities aim to remove them once the permanent cable repair is complete. PowerBack and Trident systems are built for reliable extended temporary duty with robust monitoring and protection features.
