Isolator Switch Pakistan: AC DC Solar 4-Pole
Isolator Switch Pakistan 2026 — AC, DC, Solar PV, 4-Pole Sizing & Selection Guide
Updated: May 2026 · CNC Electric Pakistan
Isolator Switch — Pakistan Quick Answer (2026)
An isolator switch is a load-break (manual) switch used to physically disconnect a circuit for maintenance or emergency. Unlike an MCB or MCCB, an isolator does NOT trip on overcurrent — it's purely a manual isolation device. Pakistan 2026 prices: AC 4P 63 A from Rs.2,200; AC 4P 100 A Rs.3,400; AC 4P 250 A Rs.6,800; DC 2P 1000 V 32 A solar isolator Rs.1,950; DC 4P 1000 V 63 A Rs.4,200; DC 4P 1500 V 125 A Rs.7,800. Always paired with a breaker — isolator handles isolation, breaker handles fault protection.
Browse: CNC Isolator Switches → · WhatsApp 0326-1111376
What an Isolator Is (and Is Not)
An isolator switch is a heavy-duty mechanical switch with one job: disconnect a live circuit so it's safe to work on. It DOES NOT:
- Trip on overcurrent (use an MCB or MCCB)
- Trip on short-circuit (use an MCCB)
- Trip on earth leakage (use an RCCB)
- Switch automatically (use an ATS / contactor)
What it DOES is provide a positive, visible, lockable break in the circuit for safe maintenance. Standard isolator features:
- Visible break: you can see through a window whether contacts are open or closed
- Padlock-able in OFF position: tag and lock out for safety per Lock Out / Tag Out (LOTO) procedure
- Load-break rated: can safely break a live load current (not just no-load contacts)
- Multi-pole: switches all phases including neutral simultaneously (4P for 3-phase + N)
Where Isolators Belong in a Pakistani Installation
Solar PV Systems — The DC Isolator
Mandatory under IEC 62548 between the PV array and inverter — the DC isolator lets installers safely disconnect the solar string from the inverter for maintenance. CRITICAL for Pakistan's solar boom — installing solar without a DC isolator is unsafe and may void inverter warranty.
- Location: directly between PV string output and inverter DC input
- Voltage rating: must equal or exceed the string Voc (open-circuit voltage). 600 V isolator for small string, 1000 V standard, 1500 V for utility-scale
- Current rating: equal or exceed the string Isc × 1.25 (NEC 690.8 derating)
Generator / ATS Maintenance Isolators
Upstream and downstream of the ATS — isolators let you safely disconnect both sources for ATS maintenance without shutting down the building. Standard practice in commercial / hospital installations.
Industrial Motor Isolators
Many factories install a local isolator next to each large motor (outside the motor control centre) so maintenance technicians can lock the supply off before working on the motor. IEC 60204-1 requires this for motors above 7.5 kW.
Air Conditioning Outdoor Unit Isolators
Standard practice: install an isolator on the wall near the outdoor AC unit. Tech turning the AC off for service uses the local isolator instead of running back to the DB box. Often paired with a 2-pole isolator in a small IP55 weatherproof enclosure.
AC vs DC Isolators — Why the Distinction Matters
You cannot use an AC isolator on a DC circuit. AC isolators are designed to break sinusoidal AC current that naturally passes through zero 100 times per second — the arc extinguishes at zero-crossing. DC has no zero-crossing, so an AC isolator opening a DC circuit creates a sustained arc that:
- Burns through the contacts in milliseconds
- Can start a fire in the enclosure
- Welds the contacts shut even if the operator releases the handle
DC isolators have purpose-built arc-extinguishing chambers — magnetic blow-out coils or chamber geometry that stretches the DC arc until it cools and breaks. ALWAYS use a DC-rated isolator on solar PV strings and battery circuits.
CNC Isolator Range — Pakistan 2026 Prices
AC Isolators (load-break)
- 4P 63 A 400 V AC isolator (YCHGL series) — Rs.2,200
- 4P 100 A 400 V AC isolator — Rs.3,400
- 4P 160 A 400 V AC isolator — Rs.5,200
- 4P 250 A 400 V AC isolator — Rs.6,800
- 4P 400 A 400 V AC isolator — Rs.10,500
- 4P 630 A 400 V AC isolator — Rs.17,500
- 4P 800 A 400 V AC isolator — Rs.24,000
- 4P 1000 A 400 V AC isolator — Rs.32,000
DC Isolators (solar / battery)
- 2P 600 V DC 32 A solar isolator — Rs.1,650
- 2P 1000 V DC 32 A solar isolator — Rs.1,950
- 4P 1000 V DC 32 A (string isolator) — Rs.3,200
- 4P 1000 V DC 63 A — Rs.4,200
- 4P 1500 V DC 63 A (utility-scale solar) — Rs.5,800
- 4P 1500 V DC 125 A — Rs.7,800
Outdoor Weatherproof Isolator Boxes
- 32 A 4P AC isolator in IP65 enclosure (outdoor AC unit standard) — Rs.3,500
- 32 A 2P DC isolator in IP65 enclosure (rooftop solar standard) — Rs.2,800
- 63 A 4P AC isolator in IP65 enclosure — Rs.5,500
Solar PV Isolator Sizing — Pakistani Standard
For a typical 6 kW residential solar install with 12 panels in 2 strings of 6 panels each, 350 W panels (Voc 40 V, Isc 10.5 A):
- String Voc: 6 × 40 V = 240 V at 25°C (rises ~15% at Pakistan's coldest morning of -2°C = ~275 V)
- String Isc: 10.5 A (each string)
- Required isolator voltage rating: 600 V DC minimum (with 100% safety margin)
- Required isolator current rating: 10.5 × 1.25 = 13.2 A → pick 16 A or 32 A standard size
- Recommended: 2P 1000 V DC 32 A isolator (Rs.1,950) — covers 4-string installations too with headroom
For commercial 10 kW+ installs with 3 or 4 strings, upgrade to 4P 1000 V 32 A or 63 A isolators. For utility-scale 1500 V systems, use the 4P 1500 V isolators.
Isolator vs MCB — Why You Need Both
| Property | Isolator | MCB / MCCB |
|---|---|---|
| Manual switching | ✅ Yes (primary use) | Yes (secondary) |
| Trips on overload | ❌ No | ✅ Yes |
| Trips on short-circuit | ❌ No | ✅ Yes |
| Padlock-able in OFF | ✅ Standard | Some models |
| Visible break window | ✅ Standard | Rare |
| Cost vs equivalent MCB | ~30% less | More expensive |
Use both together: MCB / MCCB protects the circuit against faults; isolator gives clear, lockable manual isolation for maintenance. Typical install: MCCB at the panel + local isolator at the equipment.
Common Mistakes
- Using an AC isolator on a DC solar string. Will burn through and potentially cause a roof fire. ALWAYS use a DC-rated isolator on solar.
- Skipping the isolator on solar PV systems. Required by IEC 62548 and most inverter warranties. Installers should not deliver a system without one.
- Undersizing the voltage rating. String Voc at cold ambient is 15-20% higher than the nameplate Voc at STC. A 600 V isolator on a 240 V string is fine; on a 550 V string it's too close to the limit.
- Forgetting the padlock during maintenance. Without LOTO (Lock Out / Tag Out), a colleague might switch the isolator back ON while you're working on the load. Always padlock OFF + tag with your name and contact.
- Using a 3P (not 4P) isolator on a 3-phase circuit. Neutral stays connected — you can't fully isolate the circuit, technically still live for shock purposes. Always use 4P for 3-phase + N.
- Mounting the AC outdoor unit isolator in a non-weatherproof box. Rain ingress corrodes contacts. Use an IP55 minimum enclosure outdoors.
Frequently Asked Questions
What is the price of an isolator switch in Pakistan?
CNC isolators Pakistan 2026: AC 4P 63 A from Rs.2,200; AC 4P 100 A Rs.3,400; AC 4P 250 A Rs.6,800; DC 2P 1000 V 32 A solar isolator Rs.1,950; DC 4P 1500 V 125 A Rs.7,800. Outdoor weatherproof enclosed versions add ~Rs.1,500-2,000.
What is the difference between an isolator and an MCB?
An isolator is a manual switch for safe disconnection — NO automatic protection. An MCB automatically trips on overcurrent / short-circuit. Use both together: MCB protects against faults, isolator provides lockable manual isolation for maintenance.
Do I need a DC isolator for solar?
Yes — mandatory under IEC 62548 between the PV array and inverter. Required for safe maintenance and to comply with most inverter warranties. Use a DC-rated isolator (not AC) on solar strings — AC isolators cannot safely break DC arcs.
Why can't I use an AC isolator on a DC solar circuit?
AC isolators rely on the natural AC zero-crossing to extinguish the arc when contacts open. DC has no zero-crossing — the arc sustains, burns through the contacts, and can start a fire in the enclosure. Use a purpose-built DC isolator with magnetic blow-out arc-extinguishing.
What size DC isolator for a 6 kW solar system?
For 6 kW with 2 strings of 6 × 350 W panels: string Voc ~240 V at 25°C, ~275 V at -2°C. String Isc ~10.5 A. Required: 600 V DC minimum voltage, 13 A current. Use 2P 1000 V DC 32 A isolator (Rs.1,950) — covers with safety margin and accommodates expansion.
Can the isolator be padlocked?
Yes — quality isolators (including CNC YCHGL series) have a built-in padlock hasp on the handle when in OFF position. Required for Lock Out / Tag Out (LOTO) safe maintenance procedures. Always padlock OFF + tag with your name when working on the load side.
Where should I install a 1.5 ton outdoor AC isolator?
On the wall directly adjacent to the outdoor unit, accessible to technicians. Use a 2P 32 A AC isolator in an IP55 weatherproof enclosure (Rs.3,500). Wire upstream of the AC's internal terminals — flip the isolator OFF before any servicing.
AC or DC isolator — right rating for your install
Tell us the application (solar PV, ATS, motor, AC unit) and we’ll spec the right isolator, IP rating, and enclosure.