BY1 Surge protective device
BY1 Surge protective device

Usage and application scope
BY1 series surge protective device (protector in short) is applied in A.C 50/60 Hz , 380V in the following electric
power system , such as TT , IT ,TN-S , TN-C and TN-C-S which protects the electric net shocked by the thunder or
surge over voltage .
Tripping device
There's tripping device designed on the modular of the protector. When the protector is over heat or shocked, the
tripping device can automatically separate it from the electric net, at the same time showing the indication signal. It's
green when the protector is normal, red when tripping.
The power of the alarm is supplied by AC220V. In normal condition it is green and the opening contact is closed but
the closing contact is open. It is with the function of alarming and showing: the alarm will sound and the green
indicator lamp will change to red when the mould of the protective device is out of working. And the alarm will not
stop until the operator pushes the stop press (but the red lamp is still showing). If the trouble can not be dealt within
24 hours, the alarm will sound again. Remote signaling contact
The products can be produced available with the accessory of remote signaling contact which is an opening contact. If
one of the product's mould is out of working, the contact will be closed and send the trouble information. The rated
data of the remote signaling contact is AC36V, 1A.
Principal parameters
1. Maximum continuous operating voltage Uc~140 275 320 385 420 550V
2. Test classification II grade
3. Protection level Up < 0.8 1.2 1.5 1.8 2.0 2.5kV
4. Max. discharging current (8/20s) Imax 10 40 60kA
5. Nominal discharge current (8/20s) In 5 15 20 30kA

Technical Parameters              
  BY1-D/ -140-55 BY1-D/ -275- BY1-D/ -320-5 BY1-D/ -385-5 BY1-D/ -420-5 BY1-B/ -320-30 BY1-B/ -385-30
Maximum continuous operating 140 V 275 V 320 V 385 V 420 V 320V 385V
voltage Uc 0.8 kV 1.0 kV 1.5 kV 2.0 kV 2.0 kV 2.0kV 2.5kA
Voltage protection level Up < 5 5 5 5 5 30 30
Nominal discharge current In 10 10 10 10 10 10 10
(8/20s) kA <25 Orange
Maximum discharge current Imax (8/20s) kA 18
Response time ns Yellow
Width mm IP20
Color Reinforced fire-retardant
Protection level nylon PBT
Shell material nylon PBT
Fuse Or Switch (A) 10 --- 16A
Connect ways L ,N 2.5 --- 35
Earthing 4.0 --- 35 mm2 mm2
Signal line 1.5mm2

  BY1-C/ BY1-C/ BY1-C/ BY1-C/ BY1-C/ BY1-C/
140-15 -275-20 -320-20 -385-20 -420-20 550-20
Maximum continuous operating voltage Uc 140V 275V 320V 385V 420V 550V
Voltage protection level Up < 0.8kV 1.2kV 1.5kV 2.5kV 2.5kV2 kV
Nominal discharge current In(8/20s) kA 15 20 20 20 20 20
Maximum discharge current Imax (8/20s) kA 40 40 40 40 40 40
Response time ns <25 2.5-35 mm2
Width mm 18
Color grey
Protection level IP20
Shell material enforce anti- flame PBT
Fuse Or Switch (A) 25-32A
Connect ways L ,N
Earthing 4.0 ---45 mm2
Signal line 1.5mm2

BY1 - B
The installation position and application of BY-D
1. Installed on the joint of LPZ1 or LPZ2 and LPZ3.
2. Applied in household distribution boards, computer equipment, information equipment, electronic equipment and in
the socket box in front of control equipment or near the control equipment.
The installation position and application of BY-C
1. C grade lightning current SPD protection, used for electric connection when being shocked.
2. Installed on the joint of LPZOB or LPZ1 and LPZ2.
3. Generally it's installed in the floor distribution board, computer center, telcommunication room, elevator control
room, cable TV room, floor automatic control room, guard supervising room, fire protection center, industrial automatic
control room, frequency conversion equipment control room, hospital operating room, supervising room and the
distribution board with electronical medical equipment, also can be installed in the whole distribution board under
the six floors
To the individual building, the SPD should be installed in the distribution board of every household.
The main structure and operating principle
In three- phase four- line system, three phase lines and one zero line are connected protective device to the earth
cable. (figure 1 ) . In normal situation, the protective device is high resistance, when the over voltage brings for electric
network shocked by thunder or other reasons, the protective device will rapidly transmit in ns , then lead the voltage
into earth and protect the electric equipment. As the surge voltage through the protective device and after disappear it
will recover to high resistance and not influence the normal operating. Figure 2 is the electric principle about it.

It adopts 35 mm DIN rail
It is linked by 2.5 -- 35 mm2 copper wire , and there are 2 wiring methods:
1. From power switch to protective device , then from protective device again to the load end . This way suits to the
distribution case which load current is under 100 A . The wire section should be selected by the load current .
( Figure 3 )
2. From the power switch to protective device , also from the power switch to load end . This way suits to the
distribution case which load current is over 100 A . The wire section should not be selected by the load current , but it can't be longer than 500 mm.(Figure 4 )

The earth cable should choose the double color wire which is over 4 mm2 but not longer than 500 mm .In order to
guarantee electrical network's normal operating after protective device losing efficiency , the protective device which
linked to the phase line must be connected a 32A fuse box

Appearance and installation size

Adjustment, operation, maintenance
1. There's no need to adjust the protector after installation.
2. The protector can automatically protect the electric net should it's installed rightly.
3. When operating, check whether the modular scutcheon is red, at the same time check whether the indication red light is lighting, then can change the malfunction device.