A company switch is the connection point where portable cam-lock cable feeds tie into a venue’s electrical system to power temporary equipment like touring sound, lighting, and broadcast gear. ESL Power Systems builds this equipment as the ShowSwitch™ line — 100A, 200A, and 400A standard cam-lock configurations, 60–100A pin & sleeve theatre outlets, and custom concert power distribution boards up to 1600A, all UL 891 Listed as theatrical switchboards. Choosing the wrong configuration usually shows up on load-in day, not before. The eight specs below apply to any company switch on the market; we’ve noted how the ShowSwitch line is built for each one.
| Quick answer Before you specify or purchase a company switch, confirm: incoming wire size, 200% rated neutral, isolated ground, direct-wire lugs, digital ammeter, interior work light (standard on ShowSwitch), NEMA 1 vs. NEMA 3R/3RX enclosure, and mechanical vs. electrical interlock. |
Jump to a spec:
- 1. What incoming wire size does a company switch need?
- 2. Do you need a 200% rated neutral?
- 3. Is isolated ground required?
- 4. Do you need direct-wire lugs?
- 5. Do you need a digital ammeter?
- 6. Do you need an interior work light?
- 7. Indoor or outdoor: NEMA 1, 3R, or 3RX enclosure?
- 8. Mechanical or electrical interlock?
- FAQ: Company switch specification
What incoming wire size does a company switch need?
Short answer: Match the lugs to the conductor size, count, and material of the feed actually arriving at the install — not a spec sheet from a different job.
Undersized lugs can’t accept the conductors; oversized lugs leave a loose termination. Before ordering, confirm:
- Conductor size and count of the incoming feed
- Where conduit enters the enclosure (top, bottom, or side)
- Whether the feed is aluminum or copper — lug ratings differ
ESL’s ShowSwitch line sizes line terminals by amperage rather than using one lug kit across the board, so confirming the amperage and conductor size against the table below before ordering avoids a mismatched lug kit at load-in:
| Model | Amperage | Line Terminals | Neutral | Ground |
| 3313-01 | 100A | #14 AWG – 3/0 | #6 AWG – 250 kcmil | #6 AWG – 250 kcmil |
| 3323-01 | 200A | 3/0 – 350 kcmil | #6 AWG – 250 kcmil | #6 AWG – 250 kcmil |
| 3343-01 | 400A | (2) 2/0 – 500 kcmil | (2) #2 – 600 kcmil | #6 AWG – 250 kcmil |
Do you need a 200% rated neutral?
Short answer: Yes, if the load includes dimming systems, switch-mode power supplies, LED lighting, or other equipment that generates harmonic currents — standard neutrals sized to match the phase conductors aren’t enough for loads like these.
Neutral loading should be evaluated during system design. Keep in mind that triplen harmonics [180Hz] stack directly on top of each other at the neutral node.
Note: adding a second neutral can mean six cam-lock receptacles instead of five, so this affects the panel’s physical layout, not just its wiring. On the 400A ShowSwitch (3343-01), this is built in as dual #2–600 kcmil neutral terminals rather than a single lug — flag the load profile at time of order so the correct neutral configuration ships from the factory.
Is isolated ground required?
Short answer: Yes, any time the downstream load includes audio equipment sensitive to ground-loop hum or buzz.
An isolated grounding conductor provides a dedicated grounding path for sensitive electronic equipment, helping reduce electrical noise and ground-loop issues in audio systems.
ESL offers isolated ground as a factory option on ShowSwitch: an isolated ground bus, separated from the equipment ground bonded to the enclosure, can be specified at time of order for systems feeding sensitive audio gear. Flag this requirement up front — it changes the internal bussing rather than being a field modification.
Do you need direct-wire lugs?
Short answer: Yes, if any downstream equipment doesn’t have cam-lock connectors — direct-wire lugs let bare conductor ends terminate directly, no cam adapter needed.
Company switches are built around cam-lock connectors, but not every piece of connected equipment has them. Confirm this capability if any downstream gear lacks cam connectors.
On ShowSwitch, the direct-wire lug option uses mechanical lugs rated for #6 AWG to 250 MCM — useful for older house dimmer racks or fixed distro that predates cam-lock standardization. ESL also offers reverse-gender neutral and ground configurations and a POSI-LOK™ panel option for cam terminations where a different connection style is needed.
Do you need a digital ammeter?
Short answer: Yes, if you need a real-time read of current draw — to verify loads against rated capacity or track demand changes throughout an event.
A built-in digital ammeter provides a convenient way to monitor current draw in real time, helping venue managers identify potential overload conditions before protective devices trip. Without a built-in meter, operators may need to rely on external test equipment or system calculations to monitor loading.
ShowSwitch offers a UL Listed 1/4 DIN volt-amp meter with a three-row, three-digit LED display, accurate to ±0.5% of full scale on voltage and ±2 digits on current, reading all three phases simultaneously by default. Every unit also carries door-mounted indicator lights that illuminate when each cam connector is mated and the breaker is on — a quick visual check before anyone touches a live connection.
Do you need an interior work light?
Short answer: Yes — it’s a low-cost option with an outsized effect on install speed and safety, since company switches are frequently accessed in dark venue environments: backstage, in trussing, under a stage.
An interior work light now ships as standard equipment on ShowSwitch, so this is one less option to track down separately — the chamber is lit as soon as the door opens, with no need to call it out as an add-on when specifying your unit.
Indoor or outdoor: NEMA 1, 3R, or 3RX enclosure?
Short answer: NEMA 1 for standard indoor/dry installs; NEMA 3R or 3RX if the unit will sit outside or in an exposed or corrosive location — it’s an enclosure-level construction difference, not a field retrofit.
Standard company switches ship NEMA Type 1. If the unit will sit outside or in an exposed location, specify NEMA 3R up front.
ShowSwitch’s standard NEMA Type 1 enclosure is 14-gauge steel with a powder-coated matte black finish. Full construction details are on the company switch specifications page. For outdoor work, ESL also offers a Type 3R enclosure (available in lighter colors) and a Type 3RX stainless steel enclosure for coastal air, washdown areas, or other corrosive environments where painted steel would degrade faster.
| Enclosure | Environment | Typical Use |
| NEMA Type 1 | Indoor, dry locations | Standard for most venues; ShowSwitch ships Type 1 by default |
| NEMA Type 3R | Outdoor, exposed to rain/weather | Festivals, outdoor stages, exposed perimeters |
| NEMA Type 3RX (stainless) | Outdoor, coastal/washdown, corrosive air | Long-term outdoor installs where painted steel would corrode |
Mechanical or electrical interlock?
Short answer: Most applications call for at least a mechanical interlock — it requires the intended sequence of operation without relying on a control circuit, so it still works during a control power failure. Add an electrical interlock only if the application needs the extra automation.
Interlocks help prevent unsafe operation by requiring equipment to be operated in the intended sequence. Depending on the application, interlocks may be mechanical, electrical, or a combination of both.
- Mechanical interlock: Uses physical mechanisms to prevent certain actions or switch positions until specific conditions are met. Because it does not rely on a control circuit, it continues to function even during a control power failure.
- Electrical interlock: Uses auxiliary contacts, relays, sensors, or control circuits to prevent unintended operation. Electrical interlocks can provide additional functionality and automation but depend on the proper operation of the associated control system.
ESL’s ShowSwitch ships with a mechanical, safety-interlocked door as standard. The interlock prevents making or breaking cam-lock connections under load by requiring the breaker to be opened before the door can be accessed. The operator handle is recessed so it does not protrude into narrow passageways, and the door can be padlocked for additional jobsite security. For applications requiring electrical interlocks or additional control functionality, consult ESL’s engineering team during the specification process.
FAQ: Company Switch Specification
What is a company switch used for? Connecting portable cam-lock power feeds from a venue’s electrical system to temporary equipment such as touring audio, lighting, and video gear.
Is a company switch the same as a transfer switch? No. A transfer switch selects between two power sources (such as utility and generator). A company switch distributes portable feeder cable to temporary equipment.
What amperage does ESL’s ShowSwitch line cover? 100A, 200A, and 400A in standard cam-lock configurations (models 3313-01, 3323-01, and 3343-01), 60–100A pin & sleeve theatre outlets, and custom concert power distribution boards up to 1600A.
Does ESL’s company switch carry a safety listing? Yes — ShowSwitch is UL Listed and labeled under the UL 891 standard for theatrical switchboards, which is typically required for code compliance and insurance in entertainment venues.
Does ShowSwitch include an interior work light? Yes — an interior work light is now standard equipment across the ShowSwitch line.
Final Takeaway
A company switch looks like a simple box with cam-lock connectors on it. The 8 specs above determine whether it fits the job: the wire coming in, the load going out, the environment it sits in, and how safely it fails.
ESL’s ShowSwitch line is built around these same 8 variables — model selection (3313-01, 3323-01, 3343-01, or a custom distribution board), lug and neutral sizing, grounding (including isolated ground), metering, enclosure rating, and interlock type are all confirmed before the unit leaves ESL’s Corona, CA factory, and an interior work light ships standard. Get these confirmed before you order, not during load-in.
Want to see these options on an actual unit? Watch ESL’s ShowSwitch company switch feature video, review the standard specifications and features pages at eslpwr.com, or contact ESL Power Systems at 1-800-922-4188 or info@eslpwr.com to talk through the right configuration for your venue.
