About the BY20 Surge Arrestor

The BY20 Surge Arrestor is part of the ELEHPD Surge Arrester range. BY20 Surge protective device (Surge Arrestor) BY20-40/2P BY20-40/4P Specification Type Pole No. Uc (V) In (kA) Imax (kA) Up (kV) BY20-8/1-275 1 275 2 8 ≤ 1.2 BY20-15/1-275 1 275 5 15 ≤ 1.2 BY20-40/1-275 1 275 15 40 ≤ 1.2 BY20-65/1-275 1 275 20 65 ≤ 1.5 BY20-8/1-440 1 440 2 8 ≤ 1.8 BY20-15/1-440 1 440 5 15 ≤ 1.8 BY20-40/1-440 1 440 15 40 ≤ 1.8 BY20-65/1-440 1 440 20 65 ≤ 2.0 BY20-8/2-275 ELEHPD manufactures and exports low voltage electrical products from Yueqing, Zhejiang, China, supplying distributors, panel builders, M&E contractors and OEM buyers worldwide.

Typical applications

Consumer units and distribution boards in residential buildings
Commercial and retail fit-outs where selective protection is required
Industrial control panels and machine-builder assemblies
Solar PV, EV charger and battery-storage sub-circuits
OEM equipment where a DIN-rail protective device is specified

How to specify the right Surge Arrester

Match the rated current to the circuit design current, then check the cable ampacity
Pick the trip curve to the load: B for resistive/lighting, C for general mixed loads, D for motors and transformers
Confirm the breaking capacity meets the prospective short-circuit current at the point of installation
Verify the pole configuration (1P, 1P+N, 2P, 3P, 3P+N, 4P) against the system earthing arrangement

Specifications

BY20 Surge protective device (Surge Arrestor)

Q: What is the difference between an MCB and an MCCB?

An MCB (miniature circuit breaker) is a DIN-rail device for final circuits, typically rated up to 125 A with a fixed trip curve. An MCCB (moulded case circuit breaker) is a larger device for main and sub-main distribution, usually 16 A to 1600 A, with adjustable thermal and magnetic settings and a higher breaking capacity. Use an MCB for branch circuits and an MCCB where you need adjustability or higher fault ratings.

Q: How do I choose between a Type B, C and D trip curve?

Type B trips between 3 and 5 times rated current and suits resistive loads such as lighting and heaters. Type C trips between 5 and 10 times and is the general-purpose choice for socket circuits and mixed loads. Type D trips between 10 and 20 times and is used for loads with high inrush, such as motors, transformers and large LED drivers.

Q: What does 6 kA breaking capacity mean in practice?

It is the maximum prospective short-circuit current the device can safely interrupt. 6 kA covers most domestic and light commercial installations. Where the transformer is close and the fault level is higher, specify 10 kA devices so the breaker still clears the fault without damage.

Q: Can these devices be supplied with your own brand?

Yes. OEM branding, buyer-specific labels, custom carton print and private-model numbering can be arranged on qualified order volumes.

BY20-40/2P

BY20-40/4P

Specification

Type	Pole No.	Uc (V)	In (kA)	Imax (kA)	Up (kV)
BY20-8/1-275	1	275	2	8	≤ 1.2
BY20-15/1-275	1	275	5	15	≤ 1.2
BY20-40/1-275	1	275	15	40	≤ 1.2
BY20-65/1-275	1	275	20	65	≤ 1.5
BY20-8/1-440	1	440	2	8	≤ 1.8
BY20-15/1-440	1	440	5	15	≤ 1.8
BY20-40/1-440	1	440	15	40	≤ 1.8
BY20-65/1-440	1	440	20	65	≤ 2.0
BY20-8/2-275	2	275	2	8	≤ 1.2
BY20-15/2-275	2	275	5	15	≤ 1.2
BY20-40/2-275	2	275	15	40	≤ 1.2
BY20-65/2-275	2	275	20	65	≤ 1.5
BY20-8/2-440	2	440	2	8	≤ 1.8
BY20-15/2-440	2	440	5	15	≤ 1.8
BY20-40/2-440	2	440	15	40	≤ 1.8
BY20-65/2-440	2	440	20	65	≤ 2.0
BY20-40/3-275	3	275	15	8	≤ 1.2
BY20-65/3-275	3	275	20	15	≤ 1.5
BY20-8/4-275	4	275	2	40	≤ 1.2
BY20-15/4-275	4	275	5	65	≤ 1.2
BY20-40/4-275	4	275	15	40	≤ 1.2
BY20-65/4-275	4	275	20	65	≤ 1.5
BY20-8/4-440	4	440	2	8	≤ 1.8
BY20-15/4-440	4	440	5	15	≤ 1.8
BY20-40/4-440	4	440	15	40	≤ 1.8
BY20-65/4-440	4	440	20	65	≤ 2.0

Technical Parameters

	8-275	8-440	15-275	15-440	40-275	40-440	65-275	65-440
Maximum continuous operating voltage	Uc	275V	440V	275V	440V	275V	440V	275V	440V
Nominal discharge current (8/20 µ s)	In	2	2	5	5	15	15	20	20
Maximum discharge current (8/20 µ s)	Imax	8	8	15	15	40	40	65	65
Voltage protection leve kV	Up	≤ 1.2	≤ 1.8	≤ 1.2	≤ 1.8	≤ 1.2	≤ 1.8	≤ 1.5	≤ 2.0
Response time ns	tA	<25ns
Fuse or Circuit-breaker	16Agl/Gg	25Agl/Gg	50Agl/Gg	80Agl/Gg
Operating temperature	-40℃~+80℃
Connection section	Min.1.5mm², Max.35mm²
Installation		35 mm Rail
Outer covering material	Reinforced fire-retardant nylon PBT
Defending grade	IP20

Frequently asked questions about the BY20 Surge Arrestor

What is the difference between an MCB and an MCCB?

An MCB (miniature circuit breaker) is a DIN-rail device for final circuits, typically rated up to 125 A with a fixed trip curve. An MCCB (moulded case circuit breaker) is a larger device for main and sub-main distribution, usually 16 A to 1600 A, with adjustable thermal and magnetic settings and a higher breaking capacity. Use an MCB for branch circuits and an MCCB where you need adjustability or higher fault ratings.

How do I choose between a Type B, C and D trip curve?

Type B trips between 3 and 5 times rated current and suits resistive loads such as lighting and heaters. Type C trips between 5 and 10 times and is the general-purpose choice for socket circuits and mixed loads. Type D trips between 10 and 20 times and is used for loads with high inrush, such as motors, transformers and large LED drivers.

What does 6 kA breaking capacity mean in practice?

It is the maximum prospective short-circuit current the device can safely interrupt. 6 kA covers most domestic and light commercial installations. Where the transformer is close and the fault level is higher, specify 10 kA devices so the breaker still clears the fault without damage.

Can these devices be supplied with your own brand?

Yes. OEM branding, buyer-specific labels, custom carton print and private-model numbering can be arranged on qualified order volumes.