Onesto

Surge Arrestor 10kA, 1-4 Pole, 275V/385V | Onesto SPD

R 290.90

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Poles 1P 2P 3P 4P

Uc Voltage 275V 385V

The Onesto BY7-10 Surge Protection Device is a Class II (Type 2) surge arrestor rated at 10kA, designed to protect electrical installations, distribution boards and connected equipment from transient overvoltage caused by lightning strikes and switching surges. It is suitable for domestic and light commercial TN and TT power supply networks, and offers a visual pass/fail status indicator so installers and maintenance teams can check protection status at a glance. Available in 1, 2, 3 and 4 pole configurations for 275V or 385V systems, it is a practical entry-level choice for standard distribution board surge protection.

Application: Suitable for domestic and light commercial distribution board surge protection on TN/TT networks
Key specification: 10kA maximum discharge current (Imax), Class II / Type 2 SPD
Configuration: Available in 1, 2, 3 and 4 pole versions
Voltage: 275V or 385V operating voltage options
Status indicator: Green/red indication window shows functional or failed status
Mounting: 35mm DIN rail, IP20 enclosure

Key Features

10kA maximum discharge current (8/20µs) suited to standard domestic and light commercial risk levels
Visual green (functional) / red (failed) indication window means the device can be checked without removing it from the DIN rail
PA66 UL94-V0 flame-retardant housing suited to enclosure and distribution board installation
Compact DIN rail mounting saves space in distribution boards
Suitable for TN and TT earthing systems
Wide range of pole configurations (1-4P) to match single-phase or three-phase boards

Typical Applications

Domestic distribution board protection
Small commercial and retail installations
Isolator and pump control panel protection
Protection of sensitive electronic equipment against transient overvoltage
Entry-level surge protection upgrade for older boards with no SPD fitted

Technical Specifications

Brand	Onesto
Series	BY7
Type classification	Class II / Type 2
Maximum discharge current (Imax, 8/20µs)	10kA
Maximum continuous operating voltage (Uc)	275V or 385V AC (select variant)
Poles available	1P, 2P, 3P, 4P
Status indicator	Green: functional / Red: failed
Degree of protection	IP20
Power supply network	TN, TT
Installation method	35mm DIN rail
Housing material	PA66 UL94-V0
Ambient temperature	-40°C to +80°C
Ambient humidity	5% - 95%
Altitude	≤2000m
Standard	IEC61643-11:2011, EN61643-11:2012

What's Included

1 x Onesto BY7-10 Surge Protection Device (voltage and pole configuration as selected)

Please note: DIN rail, distribution board wiring, circuit breakers and installation accessories are not included unless specifically listed above.

Installation & Compatibility Notes

Confirm your board's earthing system (TN or TT) and system voltage (275V or 385V) before ordering.
Select the pole configuration (1P, 2P, 3P or 4P) that matches your distribution board and phase configuration.
Installation should be carried out by a suitably qualified electrician in line with local wiring regulations.
Check the status indicator periodically — a red window means the SPD has operated and must be replaced.

Warranty & Support

This product is supplied with the applicable manufacturer or supplier warranty, subject to correct installation, correct application, and warranty terms.

Zisabo supplies quality plumbing, pump, filtration and electrical products with practical support to help customers choose the correct item for their application. If you are unsure whether this product is suitable, contact us before ordering and our team will assist where possible.

Need help choosing? If you are unsure whether this product is suitable for your board, contact Zisabo with your system voltage, earthing type and pole configuration, and we will assist where possible.