Zhejiang HIITIO New Energy Co., Ltd., a manufacturer of DC protection components, power semiconductor modules, and electrical distribution equipment, has added the HP plug-on Neutral Load Centers, Class 1170 to its load center lineup. The series is intended for 120/240 Vac indoor power distribution in residential and light commercial buildings, and is offered in both Main Lugs and Main Circuit Breaker configurations.
HP Plug-on Neutral Load Centers
A Plug-on Neutral Design
The defining feature of the Class 1170 series is its plug-on neutral construction, in which branch circuit breakers connect directly to the neutral bus rather than through a separate pigtail wire. This approach has become increasingly common across the load center market over the past decade, largely because it reduces the number of field-made connections inside the panel — a factor that installers and inspectors have identified as a common source of loose or overheated neutral terminations. Plug-on neutral breakers and panelboards from several manufacturers have been evaluated for this purpose, and the general design principle is discussed in trade literature covering Type BR Quick Connect Neutral load centers.
Requirements for how neutral (grounded) conductors must terminate inside a panelboard are addressed in UL 67, the Standard for Panelboards, which specifies that each grounded conductor terminate at its own individual terminal. The National Electrical Code has incorporated related marking and construction requirements into Article 408 over successive editions, a history summarized in industry commentary from IAEI Magazine. The full current UL 67 standard document is available for reference through ANSI’s standards store.
Ratings and Configuration
The Class 1170 series covers a wide span of amperage ratings and circuit counts, allowing it to serve applications from small accessory buildings to larger multi-family distribution panels. Both copper and aluminum main conductors are accommodated, and enclosures are available in five box sizes to match different rating and space combinations.
| Type | Mains Rating | Spaces | Main Wire Size (Cu/Al) | Box Size |
|---|---|---|---|---|
| Main Lugs | 125A | 12–30 | 6–2/0 AWG | B1–B4 |
| Main Lugs | 150A | 16–20 | 4–300 AWG/kcmil | B3 |
| Main Lugs | 200A | 20–42 | 4–300 AWG/kcmil | B3–B5 |
| Main Lugs | 225A | 42 | 4–300 AWG/kcmil | B5 |
| Main Breaker | 100A | 8–30 | 6–2/0 AWG | B1–B4 |
| Main Breaker | 125A | 24–30 | 6–2/0 AWG | B3–B4 |
| Main Breaker | 150A | 16–42 | 4–300 AWG/kcmil | B3–B5 |
| Main Breaker | 200A | 20–42 | 4–300 AWG/kcmil | B3–B5 |
| Main Breaker | 225A | 42–60 | 4–300 AWG/kcmil | B5 |
Enclosures are indoor-rated and finished with white flush front covers, and ground bar kits from the HTB and GB series are ordered separately according to the circuit configuration selected. National standards on how equipment is expected to be enclosed and rated for indoor service environments are outlined in NFPA’s National Electrical Code (NFPA 70) product documentation, which remains the primary framework referenced by U.S. electrical inspectors when a panelboard installation is reviewed.
Applications
According to HIITIO, the Class 1170 series is positioned for:
- Residential main service panels and sub-panels
- Light commercial tenant spaces and small offices
- Apartment and multi-family unit distribution
- Garage, workshop, and accessory building services
- Renovations and panel upgrades requiring plug-on neutral compatibility
A full specification sheet, including model numbers and terminal torque data, is published on the product’s specification page.
About HIITIO
Founded in 2018 after Hecheng Electric brought in an established R&D team, HIITIO develops high-voltage DC electrical devices for electric vehicle, solar energy, and energy storage applications, alongside its broader lineup of HVAC/R electrical components, semiconductor fuses, and power semiconductor modules. The company operates a 30,000-square-meter manufacturing facility and reports customers across more than 50 countries and regions. Related product lines include the HSN Series Plug-in Neutral Load Center, UL 489 miniature circuit breakers, and surge protection devices for solar and distribution applications.
