Questions tagged [surge-protection]

Questions about protecting electrical devices from voltage spikes.

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60 views

Varistor - Place before or after the fuse?

What is safer? Before or after the fuse? In my case the varistor is 10mm, 275Vrms, and it is currently placed after a 250Vac, 7A, 20mm glass fuse. Would the varistor blow the fuse easily if placed ...
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1answer
36 views

Understanding lower voltage’s effects

Let’s say I have a surge protector that has a 15A cable that is rated 1875 watts at 125V. If my voltage is low, let’s say 105V the amount of watts it can supply will drop? So its max safe output ...
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1answer
66 views

Why did these two ethernet switches die (again)?

For the second time in four months I find that the two ethernet switches in my family room are dead. These are Netgear GS105 unmanaged switches labeled SW1 and SW2 in the attached figure. By dead I ...
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1answer
30 views

Plastic Plugs in Surge Protectors or UPS

Would plugging 4 out of 7 outlets in a surge protector or UPS with plastic “safety plugs” to keep out dust/dirt harm the product in any way? I know that plastic is an insulator and it might affect ...
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0answers
40 views

Can we use tvs and mov together for thruster?

I want to know if we can use both tvs and mov varistor together ? What will be good for thrusters ? And placement between esc and thruster or before esc? Update: system voltage is power supply ...
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1answer
37 views

Max power from surge protector

I have a surge-protected outlet from a renowned brand. On the back it is written 10A 230v Up voltage = 0.8KV Spd class III. The 8 outlets are Shucko format. I do not understand that up voltage. ...
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1answer
35 views

Why often is used a varistor 7D471K for 220-240vac surge protection rather than a lower nominal voltage one?

In my "supposedly" surge protected power stripe there is a varistor for surge protection configured to simply short-circuit the entrance wires in case of surge. Checking the model it's a MOV-7D471K ...
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0answers
30 views

UPS vs Surge Protector regarding short circuits and quality of power

I did research before posting and it seems a UPS filters power so that it is constant and “filtered” additionally it seems to be able to protect against short circuits. Does a surge protector have ...
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1answer
35 views

I am failing to understand the difference in Impulse Sparkover voltage vs DC Sparkover voltage of GDT

Lets say I want to use a Gas Discharge tube for indirect lightning protection, and I have a tvs diode in parallel with GDT. Since this is indirect lightning and has a fast waveform, should the tvs ...
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1answer
48 views

Question related to TVS Diode in series

I have a questions on my mind, and I hope that can be answered. The line to ground voltage is 54Volt, and I would like to know if it is possible to have two bi-direction TVS diode in series. I will ...
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0answers
37 views

Anyone hear of GMOV - Metal Oxide Varistor in series with Gas Discharge tube

I am currently working on protecting the Network switch. The network switch is powering a camera outdoor. I have read through multiple tvs components, and found advantages and disadvantages. Until ...
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2answers
60 views

Two Gas Discharge Tube in parallel; a fast acting gas acting tube and a gas discharge tube

I want to know what happens if we put two gas discharge tube (fast acting GDT and a GDT in parallel), and a tvs diode in parallel. Would there be an issue in putting GDT in parallel? Datasheet of ...
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1answer
57 views

Gas discharge tube datasheet impulse sparkover specification

What does the Impulse Sparkover at 100 V/us and 1000 V/us mean? Does it have anything to do with arcing? How does the impulse help us decide with which GDT to choose?
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3answers
101 views

Circuit Protection against 500V surge

With my firm we're trying to get the CE certificate for our device and one of the tests is the protection against power surges. For this, the test company is using a device that's connected to our ...
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0answers
21 views

How do I calculation to see if Thyristor complies with DO-160G indirect lightning protection

I have been working with TVS diode and found that the capacitance of tvs diode is large; therefore, I will not be able to use tvs diode. Thyristor, on the other hand, has low capacitance for high ...
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0answers
12 views

Surge Protection in a 3 Phase TT System

I am studying on the topic of Surge Protection Device (SPD) and I just couldn't figure out the proper selection of the Type 1 L-N SPD rating for a TT-system. Assuming a lightning current (LPL 1) of ...
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1answer
52 views

DO-160 indirect lightning requirement confusion

I am looking at many tvs diode online, and I wanted to know how to calculate to check if it complies with DO-160 indirect lightning surge protection. For DO-160, there are Waveform 3, 4, 5A&B, ...
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1answer
59 views

Lightning Surge Protector that complies with DO-160. Indirect lightning waveform, Gas Discharge tube or MOV in parallel with tvs

Would it be wise to put Gas discharge tube in parallel with tvs diode? OR Would it be better to put MOV in parallel with tvs diode? Also when deciding on tvs diode, how does indirect lightning ...
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1answer
126 views

A TVS for lightning surge protection

A camera will be mounted outside and powered via POE to Aruba 2540 network switch. I don't want indirect lightning surge to travel into the network switch. I don't care if the camera gets destroyed. ...
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2answers
80 views

Using a Main Surge Protector for only branching out other surge protectors

Whenever I try to find information about this question it always says that it is not good to plug in a surge protector into a surge protector because you can overload or overheat the protector or ...
2
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1answer
76 views

230VAC line voltage sensing using MCU pin

I Am designing a circuit to detect the presence of AC line voltage.It is basically to detect the switch On/OFF for a load. Here is the circuit. Here Input resistor ladder to step down the voltage. ...
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1answer
66 views

MCU conneected to AC Mains

I am developing a PCB which is having control MCU circuit, it will control the relays. Relays output are connected to 230V AC mains load (~100W load). This PCB is mounted on a cabin where people cant ...
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1answer
41 views

How do surge protectors interact with existing circuit protection?

I recently bought a power strip with a surge protector and it came with this warning. Do not install this product if there is not at least 10 meters (30 feet) or more of wire between the ...
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1answer
30 views

Surge protector outlet with altered grounding potential

I realized that I have a voltage difference of 5 to 80 V AC (orange in Fig. 1) between the protective conductors (grounding cables, "PE-Leiter", yellow-green contacts in drawing) before vs. after a ...
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3answers
707 views

Polarity of gas discharge tubes

Do gas discharge tubes used e.g. for surge protection have a polarity, i.e., do they protect in both directions (i.e., depending which wire is hit, or if it is a positive/negative lightnings? The ...
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1answer
55 views

Grounding for surge protection for telephone/internet/data lines

After my router broke in a thunderstrorm, I am trying to establish surge protection for power lines as well as (this question) for telephone/internet lines. I found devices such as Tupavco TP302, ...
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0answers
30 views

What's the proper way of mounting surge arresters on TN-S system?

I'm attaching a diagram with surge arresters put on each line. Most of the experts in the field say a proper defense against lightnings and switching events has three surge arresters - one between ...
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1answer
62 views

Transient current capacity of sacrifical Zener diode

The common wisdom is that Zener diodes are suited for only very low power surge protection because of their low current capacity. But what about where it was used as a sacrificial device for clamping ...
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1answer
136 views

AC line surge protection with GDT in series with MOV

We often use GDT in series with MOV to protect AC lines as below. But i have Question as for 230V AC line and 275V Rated MOV - What Should be the Breakdown voltage of GDT ? Three options available :...
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1answer
24 views

Probe max voltage (50:1)

I'm preforming some measurements with a differential probe and I'm not sure what is the correct attenuation ratio I should use (measuring about 300 V voltage drop on a varistor, which is a surge ...
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1answer
23 views

Why is the ground of the component, SP1050-04BTG, connected to the Power Supply of POE?

The SP1050-04BTG is a surge protector.
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0answers
19 views

Protecting a 5.1 amplifier

Some Yamaha models have no protection at all, except a fuse, maybe. I was thinking using a GDT, MOVs plus a line filter in an external box. And maybe adding a 12v latching relay (two pushbuttons: push ...
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2answers
85 views

Does whole house surge protection device (SPD) protect from Ground (PE) surges?

I've been researching on whole house surge protection devices and came across an Illustration of lightning current flow from a direct strike near the (protected) structure. From my understanding Type ...
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2answers
172 views

Surge arrester placement in substation

Is it enough to place surge arrester on the terminals of the transformer in a substation, or every power line entering the substation should have its own?
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2answers
90 views

transient protection for 0.5W laser diode switching driver

I'm some way into a project which involves switching 0.5W laser diodes at 100kHz, with a pulse of around 1us in width. I'm having issues with the diodes (which I don't have a datasheet for) failing ...
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1answer
62 views

How to protect against line transients?

I am designing a circuit that can detect if a cable is connected to mains voltage (e.g. via an external relay or switch). The device will be installed in electric cabinets. The circuit is tested and ...
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1answer
166 views

How do I correctly protect my MCU from resetting during a current surge on RF transmission?

I designed a PCB with a SIM868 module for data transmission. On the PCB, the MCU resets randomly on transmission start of the SIM module. On a breadboard setup, it worked just fine, even without caps. ...
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0answers
57 views

Why can't I piggy back / Daisy chain surge protectors or a surge protector and an ups? [duplicate]

Assuming I don't exceed the wattage rating of the whole system then why can't a piggy back let say ups to a surge suppressor in order to let say increase the protection of my system. Let's assume: I ...
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2answers
112 views

Why the replacement of 7812 with R-78E12-0.5, DC/DC makes the circuit not working?

I have this simple surge protector and soft start inside the PSU. My transformer is out of its specifications yields 21.3V after bridge rectification. And 0.1A load (12V fan for cooling pass ...
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0answers
24 views

Medium Voltage Synchronous Motor Protection [duplicate]

How is the wound field of a medium voltage synchronous motor protected from voltage surges? We do know that the stator is protected from surges by either one of the following: 1. RC Snubber Circuit 2. ...
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3answers
2k views

Varistor? Purpose and principle

In the AL9910 LED driver datasheet it shows a part, which I assume is a varistor, is it so? Varistors are shown to be connected across L and N lines, but here it is connected in series. Please explain ...
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1answer
108 views

How do select capacitor for 400A surge currents?

I have a 220nF capacitor in a series with my surge protection circuit. As can be seen from my spice simulation, the capacitor gets a surge of current passing through it under fault conditions, and ...
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1answer
601 views

Purpose of backup fuse in SPD

I am trying to understand the main purpose of backup fuse used in SPD (Surge Protection device). Is this used to protect the SPD from high AC current but still allowing surge current to pass or does ...
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1answer
229 views

On a wire designated as '3x14AWG' what does the '3x' part mean?

On a wire designated as '3x14AWG' what does the '3x' part mean? It is on a wire that is part of a surge protector power strip.
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4answers
11k views

Is it Safe to Plug an Extension Cord Into a Power Strip? [closed]

Just a bit of context, I am a technology enthusiast. I love everything from software to hardware, Windows to Linux, Computer to Phone, and everything in between. So, I wouldn't be surprised is my ...
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0answers
113 views

Protection against ESD/EFT/Surges

One of my project architectures looks like this: GPIO / 595 output / 12 VDC wire lengths will not exceed 25 cm. I have faced MCU lockup issues due to EFT in the past and want to make sure this ...
3
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3answers
284 views

Surge Current on PCB

When designing a PCB, do you need to worry about the inrush/surge current or just the continuous/RMS current on the board? Everything I have seen including IPC documentation is for continuous current....
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1answer
58 views

Home voltage stabilizer circuit

I am designing a 12000W voltage stabilizer transformer. I saw in another design that they use on the AC neutral a 10W resistor linking on the branch on relay contacts so that the neutral is taken from ...
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1answer
166 views

How can I simplify my design for a Surge Protection Device (SPD)?

I have found a basic design for a SPD and I would like to simplify it. However, I have little experience designing SPD circuits. This is my parallel type SPD circuit with embeded LED indicator: In ...
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1answer
221 views

230VAC dimmer MOSFET failure at surge test

Our dimmer prototypes work fine, but fails surge test, as per 61000-4-5, 1/50us. Circuit is isolated dimmer for 230VAC different types of bulbs. It uses 2x N MOSFET as switch. V503 detects zero ...