Metal-clad versus metal-enclosed switchgear
In the ANSI/IEEE context described by Eaton, metal-clad construction has separately compartmentalized components and draw-out breakers. Metal-enclosed equipment can use a different compartment and switching arrangement. Specify the required construction and standard; do not treat the labels as an automatic substitution.
Arc-resistant is a separate performance requirement. Ask for the documented classification and installation conditions, including access and any required exhaust arrangement. The presence of metal compartments alone does not establish an arc-resistant rating.
Which ratings belong in the switchgear specification?
Compare assembly and device ratings on their stated bases. Continuous bus amps describe carrying duty; breaker interrupting duty and assembly short-time withstand describe different fault requirements.
| Field | What the project should identify |
|---|---|
| Voltage and insulation | Nominal system voltage, rated maximum voltage, frequency and insulation requirements |
| Continuous current | Main bus, main/tie devices and each feeder, with the applicable operating conditions |
| Fault duty | Study requirements; device interrupting duty; assembly short-time withstand and duration; peak requirements |
| One-line and lineup | Main/tie/feeder schedule, section count, bus arrangement and future expansion |
| Protection and controls | Relays, CT/PT requirements, metering, control power, interlocks, communications and transfer or synchronization scope |
| Installation and acceptance | Indoor/outdoor, access, dimensions, cable entry, environmental conditions, required tests and documentation |
Request 1200A, 2000A, 3000A or 4000A switchgear
J&J accepts switchgear requirements up to 4000A. Include the required voltage class and construction beside the current rating. A 4000A low-voltage request is distinct from a 4000A medium-voltage lineup; the actual manufacturer, configuration, fault rating and schedule must be established in the written quotation.
What should a used or surplus switchgear offer include?
Request assembly and device nameplates, general arrangement and schematics, breaker and relay schedules, service or preservation history, current photographs and available inspection and test records. Reconcile missing, replaced or modified components with the documents. Identify any retrofit work and its acceptance basis before comparing price.
- A matching breaker voltage or frame label does not establish fit in an existing cubicle.
- Agree on which devices, controls, wiring, accessories and loose parts are included.
- Separate equipment supply from site studies, installation, settings and commissioning responsibilities.
Send a switchgear requirement to J&J
Email the one-line, equipment schedule, ratings, condition preference, quantity, destination and required date to tommy@jjtransformers.com. If replacing existing gear, include the assembly and breaker records. J&J reviews supply options against the stated requirement; no ready-to-ship lineup is claimed by this guide.
Common questions
Written quotes and supporting records control unit-specific ratings, availability, condition, price, and delivery.
Are 2000A bus and 25kA fault ratings the same kind of rating?
No. Bus amperage describes continuous carrying duty. Fault ratings describe interrupting or withstand performance on specified bases. Confirm the applicable device and assembly ratings separately.
Does metal-clad mean arc-resistant switchgear?
No. Arc-resistant performance requires its own documented classification and installation conditions.
Can I buy a complete lineup or just a replacement breaker through J&J?
J&J reviews both types of requirements. Identify the requested scope, construction, ratings, existing equipment interfaces and needed date. Availability and the exact included equipment require a written offer.