Huanghua Group Co., Ltd. 
HKM7L Residual Current Operated Circuit Breaker
Product overview
This product is suitable for the low-voltage power grid system with three-phasefour-wire neutral point directly grounded (TT). It is used to protect the line orelectrical equipment from grounding fault, overcurrent, short circuit, overvoltage,undervoltage, automatic tripping and phase loss after power failure. It can alsoprovide indirect contact protection against personal electric shock.The product conforms to the standards: GB/T 14048 2, GB/T 32902, DL/T 20.Communication protocol for residual current circuit breaker.Note: This manual is applicable to both right N-type products and left N-typeproducts.
Key Highlights
Seven-fold intelligent protection: overload, short-circuit, residual current, overvoltage, undervoltage, phase loss & auto-reclosing
Triple residual-current detection: auto-tracking, sudden-change & special-wave identification
Real-time monitoring of 3-phase voltage, current & residual current with LCD wheel display
Auto-reclosing (20~60s adjustable) — intelligent power recovery after voltage normalises
Standard RS-485 + DL/T-20 communication, optional infrared for smart-grid remote O&M
Complies with State Grid Q/GDW1972 (distributed PV grid-tie) & Q/GDW11289 (lightning protection)
Ideal for distributed PV, rural low-voltage distribution, industrial & building smart distribution
Typical Applications
Three-phase four-wire TT low-voltage networks · Distributed PV grid-tie · Rural low-voltage distribution protection · Industrial/commercial smart distribution · Sites requiring RCD + smart communication
Product Features
Protection
Residual-current auto-tracking, sudden-change & special-wave detection; over/undervoltage & phase-loss protection; auto-reclosing after voltage recovery; electronic overload, instantaneous & short-delay short-circuit protection; zero-loss & power-failure trip protection.
Display
In closed state, automatically wheel-displays: rated residual operating current, rated current, current time, max leakage value & phase, 3-phase voltage & current parameters.
Setting & Query
Enable/disable residual-current alarm, auto-tracking, sudden-change, special-wave, auto-reclosing, over/undervoltage, phase loss, overload, zero-loss protection via keys or communication; query trip records, test records, total & locked trip counts.
Control
Field test-trip via [Test] key; remote reservation of open/close/test-trip/cancel; synchronous open/close via external interfaces.
Self-test
Three self-check functions: remote trial-trip, scheduled trial-trip & key trial-trip, plus voltage self-check closing.
Monitoring & Recording
Records residual current, 3-phase voltage & current daily max/min and time scale within 30 days (14 records); records parameters & time scale of nearly 10 trips.
Auxiliary
RS485 fully supports the forthcoming DL/T Residual Current Circuit Breaker Communication Protocol; meets Zhejiang Provincial specification and State Grid Q/GDW1972 & Q/GDW11289 enterprise standards.
Normal Operating Conditions
| Ambient temp. | -5℃ ~ +40℃ | |
| Relative humidity | When avg. min. temp. of wettest month ≤25℃, avg. max. relative humidity ≤90%; condensation considered | |
| Altitude | ≤ 2000m | |
| Pollution degree | Grade 3 | |
| Installation category | III | |
| External magnetic field | ≤ 5× geomagnetic field in any direction | |
Product Parameters
| Parameter | 125A | 250A | 400A / 630A / 800A | Remarks |
| Inm / Frame rated current | 125A | 250A | 400A / 630A / 800A | — |
| In / Rated current | (0.4~1)In Adjustable | (0.4~1)In Adjustable | (0.4~1)In Adjustable | Adjustable (0.4~1)In |
| Ue / Rated operating voltage | AC400V | AC400V | AC400V | — |
| Ui / Rated insulation voltage | AC1000V | AC1000V | AC1000V | — |
| Uimp / Impulse withstand voltage | 8000V | 8000V | 8000V | — |
| Icu / Ultimate SC breaking cap. | M:50kA / H:65kA | M:50kA / H:65kA | M:65kA / H:85kA | M— Standard breaking capacity (standard type) H— High breaking capacity (high interrupting type) |
| Ics / Operating SC breaking cap. | M:35kA / H:50kA | M:35kA / H:50kA | M:50kA / H:65kA | — |
| Icw / Short-time withstand | 5kA/1s | 10kA/1s | 10kA/1s | — |
| Ue / Auxiliary supply voltage | AC400V | AC400V | AC400V | — |
| Pole | 4P or 3P+N | 4P or3P+N | 4P or 3P+N | 4P or 3P+N |
Residual-current & Function Settings
| Item | Parameter | Factory default | Adjustable range | Remarks |
| I△n / Rated residual operating current | 300mA/500mA | 300mA/500mA | 10 sets of parameters are customizable (50~1000mA) | 10 sets customisable |
| Residual non-operating current | I△no = 50% I△n | — | — | I△no = 50% I△n |
| Limit non-driving time | 0.06 s | 0.06 s | 3 groups customisable (0.06/0.2/0.3 ) | 3 groups customisable |
| Delay reclosing time | — | — | 20~60 s | — |
| Motion characteristic | AC Type | — | — | AC Type |
| Product use category | B Type | — | — | B Type |
| Overvoltage protection | 275V ± 5%(Self-tuning) | Factory default: disabled | User-configurable, | User-configurable, set range 245–300V |
| Undervoltage protection | 165V ± 5% (Self-tuning) | Factory default: disabled | User-configurable, | User-configurable, set range 140–200V |
Product appearance and installation size
| Frame | L | W | H | H1 | a | b | D | L1 | L2 | H2 | e | d |
| 125A | 185 | 122 | 120 | 64 | 164 | 60 | 6×φ4 | 167 | 7 | 26 | 30 | — |
| 125A | 185 | 122 | 120 | 64 | 164 | 60 | 6×φ4 | 167 | 7 | 26 | 30 | — |
| 250A | 220 | 122 | 121 | 64 | 200 | 60 | 6×φ4 | 202 | 7 | 26 | 30 | — |
| 400A | 240 | 142 | 132 | 84 | 200 | 70 | 6×φ4 | 218 | 10 | 24 | 35 | — |
| 630A | 335 | 196 | 177 | 99 | 273 | 96 | 6×φ6 | 305 | 12 | 36 | 48 | — |
| 630A | 335 | 196 | 177 | 99 | 273 | 96 | 6×φ6 | 305 | 12 | in:38/out:39 | 48 | — |
| 800A | 335 | 240 | 179 | 108 | 271 | 116 | 6×φ6 | 300 | in:20/out:18 | in:38/out:32 | 58 | — |
Ordering Description：When ordering, specify: Model (HKM7L) + Frame current (125/250/400/630/800A) + Breaking class (M standard / H high-breaking) + Pole (4P or 3P+N) + Rated residual operating current (e.g. 300mA/500mA) + Optional functions (infrared, etc.). Example: HKM7L-400A/H/4P/300mA.
