LS LA63N-4P-D10 Miniature Circuit Breaker

Marca: LS Electric | Produs: LA63N Series MCB

Descrierea modelului:

LA63N: Cod de serie, 6kA capacitate de rupere

4P: 4-pol (3 faze + Neutru, 4 connection poles)

D10: D-curve trip, rated current In=10A

✅ Core Technical Data

📌 Application

4P MCB with D-curve, for power circuits: 3-motoare de fază, invertor intrare, transformatoare, solenoid valves and inductive load distribution. It protects 3 phases and neutral line simultaneously and prevents nuisance tripping caused by high starting inrush current. Not suitable for general lighting (C-curve preferred for lighting).

🧩 Equivalent Replacement Models

1. Legacy LS model: BKN-4P D10 (LA63N is upgraded version of BKN)
2. Alternative interne: CHINT NB63-4P D10, Delixi DZ47s 4P D10
3. Alternative importate: Schneider iC65N 4P D10, ABB S204M D10

⚠️ Selection & Note de instalare

1. D trip characteristic: Instantaneous trip at 10~16 times rated current, immune to motor starting inrush; curba C: 5~10 in; B-curve: 3~5In.
2. 4P feature: Neutral line disconnects together with phase conductors for safe maintenance; 3P+N is available if neutral disconnection is not required.
3. Breaking capacity 6kA: Sufficient for factory end cabinets and small power panels; upgrade to LA63H (10cel) when short-circuit current exceeds 6kA.
4. No residual current protection. If earth leakage protection is needed, select LA63N series RCBO.

📦 Customs HS Code Reference

8536200000 (De joasă tensiune întrerupător de circuit, rated voltage ≤1000V)

🛠️ Troubleshooting

Trips immediately upon closing: Scurt-circuit / load earth fault

Trips when motor starts: Verify wrong C-curve selection or excessive line voltage drop

Trips after running for a period: Supraîncărcare, check if continuous load current >10O

Can Schneider MCB E9CN-4P-C16 directly replace LA63N-4P-D10?

Concluzie: Direct replacement is NOT allowed

Although the DIN rail dimension, pole count and breaking capacity allow physical fitting, rated current and trip curve are inconsistent, leading to mismatched protection characteristics.

Parameter Comparison

Two Replacement Options

✅ Option1: Fully equivalent replacement (Recomandat, unchanged protection)

Schneider part: E9CN-4P-D10

In=10A, D trip, 4P,6cel; electrical protection fully matches LA63N-4P-D10 for direct swap.

⚠️ Option2: If E9CN-4P-C16 must be used (Rarely acceptable)

All conditions below must be satisfied:

1. Continuous operating current of load ≤10A
2. Cable and terminal rating re-checked for 16A
3. Load is NOT direct-on-line motor / transformer or high-inrush inductive load (otherwise trip on startup)
4. Drawings, protection schedule and test certificates updated and re-approved

Not recommended for industrial power circuits.

Note suplimentare

1. Thermal overload curve is identical for C and D types. Difference lies only in instantaneous magnetic short-circuit trip.
2. Terminal capacity is similar, top-in bottom-out wiring compatible.
3. Same HS code: 8536200000.

How to identify load type for proper MCB selection

Core workflow: Classify load type → Determine continuous operating current → Select trip curve (B/C/D) → Choose rated current In → Verify short-circuit breaking capacity Icn → Select pole count

1. Identify Load Type & Corresponding Trip Curve

Thermal overload protection is identical for B/C/D; difference is instantaneous magnetic trip for short circuit/inrush current.

Quick reference:

Sarcini rezistive (încălzitoare, incandescent lamps) → C-curve

Inductive loads with high inrush (motoare, transformatoare) → D-curve

Precision low-power DC/electronic circuits → B-curve

2. Calculate Load Current and Select MCB Rated Current In

1) Sarcină rezistivă (Heater, Resistor) Monofazat

Simplified estimation for 380V 3-phase motor: ~2A per kW

Exemplu: 3kW 3-phase motor, rated current≈6A; starting current ~6~8×In → D-curve selected.

Selection rule: MCB rated current ≥ motor rated current and withstand starting inrush.

Nota: MCB mainly provides short-circuit protection. Motor overload shall be protected separately by thermal relay. MCB is NOT intended as primary overload protection for motors.

Margin Rule

Continuous duty load: În ≥ 1.1 × continuous load current

Intermittent load: In ≥ continuous load current

❌ Never arbitrarily increase In: Cable ampacity must match MCB rating. Otherwise cable burns without breaker tripping.

3. Select Pole Count

1P: Protect phase only, neutral permanent connection; for lighting

1P+N: Phase and neutral wired into breaker, phase protected only; circuite prize

2P: Fază + neutral both protected, simultaneous disconnection; single-phase equipment

3P: 3-faza cu 3 fire, disconnect three phases; 3-motoare de fază

3P+N: 3 faze + neutru, neutral not disconnected; balanced 3-phase distribution

4P: 3 faze + neutru, neutral disconnects together; TN-S system, full isolation for maintenance, UPS and 3-phase inverter input

LS LA63N-4P-D10 above: 4-pol, neutral synchronized disconnection.

4. Short-circuit Breaking Capacity Icn (Often Overlooked)

Icn: Maximum short-circuit current the breaker can safely interrupt.

End cabinet / ordinary workshop distribution: 6cel (LS LA63N, Schneider E9CN are 6kA) sufficient

Near transformer or main panel with high prospective short-circuit current: Select 10kA,15kA models

If actual short-circuit current MCB Icn: Breaker may fail and explode during short circuit, cannot cut fault.

5. On-site Checklist for Load Identification

✅ Check equipment nameplate:

1. Resistive or coil/motor/transformer load
2. Tensiune nominală, curent nominal, puterea nominală
3. Starting method: DOL / Star-delta / Starter moale

DOL motor has maximum inrush → D-curve; soft starter reduces inrush, C-curve acceptable in some cases

✅ Field judgment:

Obvious hump and current surge at power-on → High-inrush inductive load → D-curve

Smooth startup without current spike → Resistive / general power supply → C-curve

6. Common Pitfall Case (Matching previous model comparison)

Original circuit: LS LA63N-4P-D10 (10A D-curve)

Încărca: Small DOL 3-phase motor

If replaced with Schneider E9CN-4P-C16:

1. In rises from10A→16A: Overload protection threshold increased, original cable loses overload protection
2. C-curve magnetic trip at5~10In: Motor starting inrush may fall into instantaneous trip range → Trip immediately on startup
3. Full MCB Selection Procedure
4. Identify load type: Rezistiv / Inductiv (Motor/Transformer) / Electronic
5. Read nameplate power/current and calculate continuous operating current
6. Select trip curve B/C/D based on inrush characteristic
7. Choose MCB rated In and verify matching cable ampacity
8. Calculate prospective short-circuit current at installation point and select Icn
9. Select pole count according to distribution system (TN-S/TN-C) and maintenance requirement
10. Derating check: Ambient temperature and derating for densely mounted breakers in cabinet

Factors to consider for MCB pole selection

Core concept: Pole count defines which conductors are switched and protected. Selection shall consider distribution system type, tipul de sarcină, maintenance safety, neutral fault current and protection requirements.

Available poles:1P,1P+N,2P,3P,3P+N,4P

1. Distribution System Type (TN-C / TN-S / TN-C-S)

Primary criterion, determines whether neutral line can be disconnected.

TN-C (Combined PEN): PEN conductor must NOT be disconnected. Do NOT use 2P/4P with neutral switching; PEN remains continuous.

TN-S / TN-C-S (Separate N and PE): Neutral is independent. Decide whether to switch neutral according to requirement.

If neutral may carry overvoltage/fault current and full isolation required during maintenance → 4P (3-fază)/2P(monofazat)

Balanced 3-phase load with negligible neutral current, neutral disconnection unnecessary →3P+N (neutral passes through without switching)

2. Single-phase or Three-phase Load

Single-phase load: 1P,1P+N,2P

1P: Only phase conductor disconnected, neutral remains connected. Risc: Neutral may become energized if upstream neutral breaks; mainly for lighting.

1P+N: Phase and neutral connected to breaker, only phase has protection, neutral no overload/short-circuit protection, poles open simultaneously.

2P: Both phase and neutral protected and switched together; preferred for sockets and single-phase equipment requiring full isolation.

Three-phase load:3P,3P+N,4P

3P: Protect and disconnect three phase conductors only; balanced 3-phase motors without neutral.

3P+N: 3 phases protected, neutral wired into breaker but neutral has no overload/short-circuit protection, may switch together or pass through; for unbalanced 3-phase load.

4P: L1/L2/L3+N all protected, phase and neutral disconnect simultaneously. LS LA63N-4P belongs to this type.

3. Siguranta intretinerii (Critic)

Full isolation required: All conductors de-energized after breaker OFF. Single-phase →2P; Three-phase →4P.

Exemplu: Inverter input, UPS, main power of control cabinet. 4P full pole disconnection required before cabinet opening for service.

Ordinary end motor without neutral: Only three phases need isolation for maintenance; 3P is sufficient.

⚠️ Atenție: 1P breaker leaves neutral connected to upstream system. If upstream neutral is broken, equipment may become energized. 1P is not recommended for maintenance access.

4. Neutral Overload, Short-circuit and Harmonic Current

Unbalanced 3-phase load, large quantity of VFD / comutarea sursei de alimentare: Heavy harmonic current flows on neutral, neutral may overload.

✅ Neutral conductor requires protection → 4P MCB.

Balanced pure 3-phase motor load, almost zero neutral current: 3P sufficient, no need for 4P.

Typical scenario: Control cabinet with many PLC, DC power supplies. Third harmonic summation makes neutral current even larger than phase current → 4P required to protect neutral.

5. Compatibility with Earth Leakage Protection (RCBO / MCB+ELM)

Residual current detection requires sensing all incoming and outgoing currents including neutral.

Single-phase RCBO: Usually 1P+N or 2P

3-phase earth leakage: 3P+N /4P. Neutral must pass through CT, otherwise leakage protection fails.

If leakage module is planned, pole configuration must include neutral wire.

6. System Overvoltage & Isolation Requirement

Surge risk, reverse voltage, dual power transfer circuit: Full pole disconnection (2P/4P) recommended to prevent voltage backfeed via neutral and damage downstream equipment.

Ordinary power circuit without special overvoltage risk: 3P acceptable.

7. Cost and Cabinet Space

Wider pole count occupies more DIN rail space:

3P:54mm; 3P+N:72mm;4P:72mm

Cost ranking:4P＞3P+N＞3P. 3P/3P+N preferred for space saving when neutral protection is unnecessary.

8. Distinguish 3P+N vs 4P (Most Confused for 3-phase Circuits)

LS LA63N-4P-D10: 4P, neutral protected and fully switched, suitable for inverter input and 3-phase circuits with neutral requiring maintenance isolation.

✅ Quick Pole Selection Checklist

1. Single-phase or three-phase load?
2. Distribution system TN-C / TN-S? Is neutral disconnection permitted?
3. Neutral present? Heavy harmonic / unbalanced neutral current? Neutral protection required?
4. Full isolation required during maintenance?
5. Earth leakage accessory planned? (Neutral must pass through CT)
6. Space and cost evaluation

Typical Application Reference

1. 3-phase induction motor without neutral: 3P MCB D-curve
2. Main power of control cabinet with many switching power supplies, high harmonic, cabinet opening for maintenance: 4P MCB
3. Ordinary 3-phase lighting, unbalanced load with low harmonic:3P+N C-curve
4. Single-phase socket circuit:2P C-curve /1P+N RCBO