LV & MV Cable / Generator Tap Boxes
Safe, Custom-Built Cable Connections to a Common Bus.
A cable tap box connects multiple cables to a common bus, allowing power to be distributed or branched safely from a primary source to multiple circuits. Spike Electric fabricates all bus in-house on a CNC bus-bar punching machine, so hole patterns and cable configurations are fully customizable to your project. Standard designs typically ship within about four weeks after approval drawings, with expedite options available.
Spike offers both low-voltage (240–600 V AC / up to 1000 V DC) and medium-voltage (up to 38 kV) configurations, engineered and tested to the applicable standards for reliable, safe cable connections in demanding indoor and outdoor environments.
PowerClad supports both new construction and the replacement of older air-break, minimum-oil, or SF6 switchgear — providing higher insulation levels in less space and reducing overall switchgear footprint for significant space savings.
Thoroughly Tested, Flexible, and Built for Performance
At Spike Electric, reliability is engineered into every component. PowerClad Metal-Clad Switchgear undergoes extensive quality-assurance testing to verify performance across all critical conditions, and is built with adaptability in mind so customers can choose the features, accessories, and configurations that best suit their application.
Testing capabilities include:
- Dielectric testing
- Power-frequency withstand testing
- Mechanical endurance and functionality
- Optional factory witness testing upon request
Optional accessories and enhancements:
- Silver or tin-plated bus options
- Insulated bus with protective boots over joints
- 80 kA momentary bus rating
- Enhanced arc-safety features
- Tamper-resistant hardware
- Additional control switches and monitoring components
Need help selecting the right Cable / Generator Tap Boxes?
Our team can help you choose the right configuration for your facility or project.
Load Interrupter Switch Fuses
Fused configurations use current-limiting AC fuses of the backup type, which interrupt fault currents from their maximum interrupting current (I1) down to their minimum interrupting current (I3). They protect against high-magnitude electrical faults by sharply limiting thermal and magnetic influence, and are used to protect transformers, potential and control transformers, motors, capacitors, cables, and distribution systems.
Each fuse has a patented striker and indicator system: when the fuse element operates under a fault, the striker pin extends to activate the disconnector's three-phase trip mechanism — preventing single-phasing — and provides a visual (and, with limit switches, remote) indication that the fuse has operated. For proper coordination, a factor of at least 1.6× rated current is recommended between series fuses. Because fuses do not clear low-magnitude or ground faults, low-voltage-side secondary protection should also be provided.
Configurations
Select a configuration for its ratings, enclosure options, and spec sheet. All configurations share the fabrication, customization, safety, and quality practices in the shared sections below.
- Low-Voltage Cable Tap Box (Power Connect)
- Medium-Voltage Cable Tap Box (VoltConnect Pro MV Junction Box)
Spike's Power Connect cable tap box is a UL 50E enclosure that connects multiple cables to a common bus, with a NEMA-style hole pattern for crimp or mechanical lugs and fully custom bus patterns.
- Voltage: 240 / 480 / 600 V AC; up to 1000 V DC
- Ampacity: 600, 1600, 2500, 4000, 5000, and 6000 A (custom up to 12,000 A — contact the SEC factory)
- Short-circuit bracing: 100 kAIC
- Busbar ambient temperature: 50°C (higher ratings available on request)
- Bus & insulation: Copper tin-plated bus; Glastic insulators
- Enclosure: 0.104 in. carbon steel; NEMA Type 3R, 12, and 13; NEMA 4 or 4X outdoor; IP55 — optional stainless NEMA 4X, non-ferrous aluminum, and custom colors
- Certifications: UL 50E; IEEE C37 assembly compliant; ANSI C57.12.28; CSA Type 3R/12; IEC 60529; NEC & NFPA
- Options: Neutral bus, insulated bus, bus boots, IR windows, voltage LED indicators, gland plates, rodent barriers, pre-installed lugs, light-kit provisions
- Warranty: 1 year from date of ship
The VoltConnect Pro MVJB Series provides a secure, accessible point for connecting and disconnecting medium-voltage cables, with full customization for cable configuration and environment.
- Voltage: 1–38 kV (maximum 38 kV)
- Current: Up to 1200 A
- Enclosure: IP66-rated; available in a range of NEMA ratings, including hazardous-location options on request
- Features: Exterior voltage indicators, custom cable connections, interior cable stress-relief brackets
- Standards: Built to IEEE standards; ETL / UL listed
- Options: Neutral bus, insulated bus, bus boots, IR windows, voltage LED indicators, gland plates, rodent barriers, pre-installed lugs, light-kit provisions
- Warranty: 1 year from date of ship
Resource Download: VoltConnect Pro MVJB Series Catalog (PDF)
Also Known As
Cable tap boxes and MV junction boxes are known across the industry by many names, including: bussed junction box, generator tap box, bus duct cable tap box, busway cable tap box, electric junction box, medium-voltage splice box, MV cable junction unit, MV cable tap enclosure, MV cable branching box, MV cable distribution box, MV power connection box, and MV cable interface unit.
Grounding & Safety
Every tap box is engineered with a robust grounding system designed to safely dissipate electrical faults and minimize shock risk, with ground studs on the door and body. Designs meet or exceed applicable industry standards for electrical safety, protecting both the electrical system and the people who work on it.
Built In-House. Customized to Your Project.
Spike fabricates all bus in-house on a CNC bus-bar punching machine, so we can match virtually any hole pattern, lug type, or cable configuration. A team of degreed engineers works directly with you to tailor each tap box to your voltage, current, and environmental requirements — rather than forcing a fixed, off-the-shelf design. Standard designs typically ship within about four weeks after approval drawings, with expedited options available.
Quality & Testing
- Manufactured under an ISO 9001-certified quality management system
- Rigorous QA/QC — including Hi-Pot testing on LV assemblies and in-house Factory Acceptance Testing (FAT) on MV assemblies
- Post-shipment engineered drawings and QA/QC documentation provided for installation and maintenance
- 1-year warranty from date of ship
Industries & Applications
Tap boxes and MV junction boxes are used wherever multiple cable connections must be made safely to a common bus:
- Industrial plants and manufacturing facilities
- Commercial buildings and complexes
- Data centers and mission-critical infrastructure
- Utilities, substations, and grid connection points
- Renewable energy — wind farms and solar arrays
- Generator connection / tap applications
- Lighting, security, and data-communication systems (low voltage)