What an NVR Panel Is, and What We Build

NVR full form is No Volt Relay. An NVR panel automatically switches OFF the incoming supply when power fails or turns unhealthy — single phasing, under-voltage, over-voltage — and prevents the system from restarting until supply is restored to healthy condition. The danger it removes is the unsafe automatic restart: equipment left in the ON position slamming back to life the moment an unstable supply returns, often several times in a row as the grid flickers.

Wisdom Techno Solutions manufactures NVR panels at our Vadodara works for solar, industrial and commercial installations. A contactor carries the load; voltage-monitoring and phase-failure relays with settable thresholds watch the supply; on any unhealthy condition the contactor drops out instantly, and it stays out until all three phases return healthy — with manual or supervised re-close where the application demands it. Built in powder-coated CRCA enclosures, IP54 indoor / IP65 outdoor, with devices per IEC 60947 and IS 8623.

  • Instant disconnection on power failure, single phasing, under- or over-voltage
  • No automatic restart until every phase is back within healthy limits
  • Settable voltage and time thresholds on the monitoring relays
  • Protects inverters, UPS systems, battery chargers, motors and pumps
  • Indoor and outdoor enclosures, wall mounted
  • IEC 61439-1 assembly practice, routine tested before dispatch

NVR Panel Technical Specifications

The table below is the standard build. Contactor rating, relay thresholds and re-close logic are set from the protected equipment's rating and the site's supply behaviour.

ParameterSpecification
Board type NVR panel — disconnects the incoming supply on failure or voltage fault and blocks restart until supply is healthy
Full form NVR = No Volt Relay (also called no volt release)
Protects against Power failure with unsafe auto-restart, single phasing, under-voltage, over-voltage, phase unhealthiness
Protected equipment Inverters, UPS systems, battery chargers, motors, pumps and other sensitive loads
Operating logic Contactor drops out on supply loss or fault; restart only after all phases return healthy — manual or supervised re-close as specified
Monitoring relays Voltage monitoring / phase-failure relays with settable thresholds
Rated voltage up to 690 V AC, 50 Hz
Enclosure Powder-coated CRCA sheet steel, indoor and outdoor execution
Ingress protection IP54 indoor; IP65 outdoor
Component standards IEC 60947 and IS 8623 compliant switchgear and relays
Assembly practice IEC 61439-1 practice
Testing Routine tests and inspection at the works before dispatch, with test report
Facility Kotambi, Vadodara, Gujarat, India
Delivery 6 to 7 weeks from drawing approval, subject to switchgear availability

NVR vs AMF — Different Jobs on the Same Problem

NVR PanelAMF Panel
When supply failsDisconnects the load and blocks restartStarts the DG set and transfers the load
GoalProtect equipment from unhealthy supply and unsafe restartKeep the plant running on backup power
RestartOnly when supply is healthy — manual or supervisedAutomatic retransfer when mains returns
Typical usersPumps, chargers, inverters, standalone machinesFacilities with DG backup

Many sites need both: the AMF panel keeps critical load running on the DG, while NVR protection keeps non-critical machines from restarting into a bad supply. For generator changeover logic in detail, see the AMF vs ATS vs DG synchronization guide.

Where NVR Panels Are Used

Agricultural and industrial pump sets where single phasing burns motors; solar plants protecting inverters and battery chargers from grid disturbances; workshops and standalone machines that must never self-start after an outage for operator safety; and commercial installations where voltage fluctuation is routine. Anywhere the question is "what happens to this machine when bad power comes back", the NVR panel is the answer.

What to Send for an NVR Panel Quotation

The protected equipment and its rating (kW / A), the supply details (voltage, phases), the trip thresholds you want (or ask us to propose from the equipment rating), the re-close policy — manual, supervised or delayed automatic — and indoor or outdoor mounting. Send it through the Get a Quote form.

How Wisdom Techno Solutions Builds NVR Panels

The same works discipline as our LT switchboards: devices per the approved bill of material, ferruled and labelled wiring, IEC 61439-1 assembly practice, routine tests including functional verification of the trip and re-close logic on every panel, and the test report shipped with the board.

Related Technical Guides

Related Panel Types

If this is not the right fit for your layout, these are the related products we build to the same standard:

Send Your Single Line Diagram

Email your single line diagram, load list and system fault level and our engineers will come back with a technical offer. Not sure what to send? See what a panel manufacturer needs in order to quote accurately.

Manufacturer Wisdom Techno Solutions
Works Plot 9, Nilkanth Industrial Park 1, near Kotambi Stadium, Kamrol, Kotambi, Vadodara, Gujarat 391510, India
Email connect@wisdomtechnosolutions.com
Phone +91 80002 29727
Working hours Monday to Saturday, 8:00 am to 5:00 pm IST
Delivery lead time 6 to 7 weeks from drawing approval, subject to switchgear availability

Frequently Asked Questions About NVR Panels

What is the full form of NVR in electrical?
No Volt Relay — also called no volt release. An NVR panel disconnects the incoming supply when power fails or turns unhealthy, and prevents the equipment from restarting until the supply is restored to healthy condition.
What does an NVR panel protect against?
Unsafe automatic restart after a power failure, single phasing, under-voltage, over-voltage and phase unhealthiness. When any phase goes bad, the contactor drops out instantly and stays out until all three phases are back within healthy limits.
Why is preventing auto-restart important?
Equipment left switched ON restarts the instant supply returns — often into an unstable grid that fails again seconds later. Repeated slam-restarts burn motor windings, damage inverters and chargers, and can be an operator-safety hazard on machines. The NVR panel makes the restart a deliberate, healthy-supply event.
Where are NVR panels used?
Pump sets where single phasing burns motors, solar plants protecting inverters and battery chargers, workshops and standalone machines that must not self-start, and commercial sites with routine voltage fluctuation.
What is the difference between an NVR panel and an AMF panel?
The NVR panel disconnects and blocks restart until supply is healthy; the AMF panel starts a DG set and transfers load so the plant keeps running. They solve different halves of the same power-failure problem, and many sites use both.
Are the trip thresholds adjustable?
Yes — the voltage-monitoring and phase-failure relays have settable voltage and time thresholds, set at the works from the protected equipment's rating and tuned at commissioning to the site's supply behaviour.
What ratings and enclosures are available?
Panels up to 690 V AC, contactor-rated to the protected load, in powder-coated CRCA enclosures — IP54 indoor, IP65 outdoor, wall mounted. Devices conform to IEC 60947 and IS 8623 and the assembly follows IEC 61439-1 practice.
What should I send to get a quotation?
The protected equipment and its rating, supply voltage and phases, the trip thresholds or a request for our proposal, the re-close policy, and indoor or outdoor mounting — through the Get a Quote form.

Page updated: 17 September 2026