1P+N MCB 10A-40A | Compact Circuit Breaker

CNC 1P+N MCB — Single Module Live and Neutral Breaker

The CNC YCB9N-40 is a 1P+N miniature circuit breaker that disconnects both live and neutral in a single 18mm DIN-rail module. It provides the same overload and short-circuit protection as a standard single-pole MCB while also switching the neutral — an important safety feature for Pakistani wiring where phase and neutral are frequently reversed at the meter or junction box.

Because it takes only one DIN-rail module instead of two (as a true 2 pole MCB would), you can fit twice as many protected circuits into the same DB box. This makes 1P+N MCBs the go-to choice for apartment panels, compact residential DB boxes, and retail shops where DIN-rail space is tight.

Available from 10A to 40A with C-curve trip response, the YCB9N-40 handles general lighting, socket, AC, and inverter output circuits across Pakistani homes. CNC Electric is a trusted MCB brand in Pakistan with a 5-year replacement warranty on all circuit breakers.

Specifications

1P+N vs True 2 Pole — What's the Difference?

Both 1P+N and true 2 Pole MCBs disconnect live and neutral together, but they are not electrically identical:

Rule of thumb: use 1P+N for individual branch circuits in space-constrained DB boxes; use a true 2 Pole MCB for the main incomer where both poles should have independent overload protection.

Amperage Selection Guide

Where to Use 1P+N MCBs

Apartment and compact DB boards: a 12-way DB box that would only fit 6 circuits with true 2 Pole MCBs can fit 12 circuits with 1P+N MCBs — because each takes one module instead of two.

Bathroom and kitchen circuits: safety-critical circuits where the neutral needs to disconnect on trip. Pair with an RCBO earth leakage breaker for complete shock protection in wet areas.

Solar inverter sub-DB output circuits: the AC output from a solar inverter can be distributed through a sub-DB using 1P+N MCBs. See also solar DB bundles.

Retail, office, and POS circuits: individual cash-counter, computer, and display-lighting circuits that need full neutral isolation for safe maintenance.

Extension board and UPS output protection: where a true 2P MCB would take too much space in the parent enclosure.

Why C-Curve Matters in Pakistan

Pakistani circuits typically run a mix of lights, fans, ACs, refrigerators, and inverters. Inverter ACs and fridge compressors draw high inrush current on start-up (up to 10× rated current for a fraction of a second). A C-curve MCB tolerates this inrush without nuisance tripping — trips only on sustained overload (5-10× rated) or short-circuit fault.

B-curve (trips at 3-5×) is too sensitive for motor loads and would trip every time the AC compressor starts. D-curve (trips at 10-20×) is for heavy industrial inrush (welders, transformers) and misses general overloads. C-curve is the correct choice for every residential and light commercial branch circuit in Pakistan.

Related Products

• Branch circuits live-only → 1 Pole MCB 2A-63A (Rs.425)
• Main incomer with both poles protected → 2 Pole MCB 10A-63A (Rs.850)
• Three-phase circuits → 3 Pole MCB or 4 Pole MCB
• Earth leakage / shock protection → RCBO breakers
• Voltage protection → VA Protector
• Surge / lightning protection → SPD surge protectors
• Complete DB setup → DB boxes + MCBs
• Solar DC side → DC circuit breakers
• Read our guide → Types of Circuit Breakers in Pakistan

Frequently Asked Questions

What is a 1P+N MCB?

1P+N MCB is a miniature circuit breaker that combines one protected pole (live) and one switched pole (neutral) in a single DIN-rail module just 18mm wide. When the breaker trips on overload or short circuit, both the live and neutral conductors disconnect together — but only the live pole has independent overload detection. Because the whole device occupies a single module, it lets you fit twice as many protected circuits into the same DB box compared with a true 2 Pole MCB.

What is the difference between 1P+N and 2 Pole MCB?

A 1P+N MCB has one protected pole with overload detection and one switched pole that follows the live — it occupies 1 DIN-rail module. A true 2 Pole MCB has two independently protected poles, each with its own overload detection — it occupies 2 modules. For branch circuits needing a neutral break, 1P+N saves space. For main incomers where both poles should be independently protected, a true 2 Pole MCB is recommended.

Why choose 1P+N instead of a plain 1 Pole MCB?

In Pakistani wiring, phase and neutral are sometimes reversed at the meter or junction box. A plain 1 Pole MCB only disconnects the terminal it is wired to — if that terminal is carrying the neutral by mistake, the circuit stays live even after tripping. A 1P+N MCB eliminates that risk by always disconnecting both conductors, making it safer for residential branch circuits and circuits accessed by non-technical users.

What is the 1P+N 40A MCB price in Pakistan?

The CNC YCB9N-40 1P+N MCB 40A is available at Rs.825 at CNC Electric Pakistan. Competitor brands: Schneider iC60N 1P+N 40A typically costs Rs.2,200-2,800, and Chint NB1 1P+N 40A costs Rs.1,100-1,300. CNC offers equivalent IEC 60898 certified performance at a significantly lower price with a 5-year replacement warranty included.

Can I use 1P+N MCB as a main incoming breaker?

Not recommended. For the main incoming breaker, use a true 2 Pole MCB (up to 63A) or an MCCB (above 63A). The main incomer should have independent overload protection on both conductors — a 1P+N only protects the live pole. Use 1P+N for downstream branch circuits, not as the first breaker after the WAPDA meter.

Does the 1P+N MCB protect against electric shock?

No. The 1P+N MCB, like any standard MCB, protects only against overload and short circuit. It will not trip on earth-leakage currents of 30mA that cause electric shock. For bathroom, kitchen, and outdoor circuits, pair the 1P+N MCB with an RCBO earth leakage breaker for complete shock protection.

Can I use 1P+N MCB on a solar inverter circuit?

Yes on the AC output side of a solar inverter, for individual sub-DB distribution circuits. For the main AC output from the inverter to the DB, use a true 2 Pole MCB. For the DC side (panels to inverter), never use an AC MCB — use purpose-built DC circuit breakers rated for 500V, 1000V, or 1500V depending on your string configuration.

How wide is the 1P+N MCB on the DIN rail?

The CNC YCB9N-40 1P+N MCB is 18mm wide — one single DIN-rail module. A 12-way DB box fits up to 12 of these breakers, compared with only 6 true 2 Pole MCBs (which are 36mm each). This module-saving advantage is the main reason 1P+N breakers are preferred in apartment and compact residential DB panels.