I wanted to learn how to test an x2 capacitor, now I know as a safety capacitor. This is one of the best videos I’ve watched this new week.

If the x2 cap shorts it may trip the panel board circuit breaker but the fuse in your circuit will remain unharmed. 😅 Additionally, the neutral is bonded to ground at the panel, the sine wave oscillates between a positive and a negative voltage in reference to the neutral/ground.

@geoffedwards189

Жыл бұрын

Hello Kevin. Could you please explain about bonding of the neutral to ground at the panel. How exactly is that done? With thanks.

@KevinWorrell

Жыл бұрын

​@@geoffedwards189 In the USA, the electrical panelboard is the central hub that distributes electricity throughout a building or residence. It is typically connected to the utility power supply via a main service cable, which consists of two hot wires, one neutral wire, and one ground wire. At the main panelboard, the neutral and ground buss are at the same potential, which means they are electrically connected or bonded together. This is because the neutral wire carries the return current from the loads in the building back to the utility, while the ground wire is used for safety purposes, such as providing a path for fault currents to flow back to the source and trip the circuit breaker. However, at sub-panels, the neutral and ground buss are not bonded together, which means they are kept separate. The reason for this is to prevent any potential difference between the neutral and ground wires from causing an electrical shock hazard. This is achieved by connecting the ground wire to a separate grounding electrode, such as a grounding rod or a metal water pipe, which is then connected to the earth. In summary, the main panelboard in the USA has the neutral and ground buss bonded together, while sub-panels have them separated to prevent electrical shock hazards.

Fuse on wrong side, but good information.

Cheers Paul but should the X2 not be placed after the fuse? It won't blow otherwise, surely.

@barnabywilde374

Жыл бұрын

Agreed.. the fuse would likely survive as there'd be nothing going thru it.

Fuse is in the wrong place. It needs to be in-line with the capacitor for it to pop when the safety cap fails short.

@barnabywilde374

Жыл бұрын

exactly!

If the X2 cap goes short in your drawing how will it blow the fuse? Shurley it will blow a fuse in the supply/plug not the one in your circuit?

I've heard of these but never saw explanation like this - thanks!

So if I understand you correctly: if the x class capacitor has failed, there would be continuity across it and if the Y class cap fails then there wouldn't? Sorry I'm a newbie here, but trying to understand why my electric line trimmer failed.

PAUL< When the Y-Safety capacitor fails OPEN, how would anyone know that the safety capacitor has failed open? because the AC line 120VAC is still going into the circuit under test and the fuse never blew. I'm not sure how the Y-Safety capacitor would protect the circuit under test from voltage spikes, voltage surges, over voltage because one the Y-Safety capacitor has Failed Open and Multiple voltage spikes, voltage surges, over voltage happens after its going to damage the circuit under test right?

@learnelectronics

Жыл бұрын

The safety in the safety cap is it. It saves you from being electrocuted. It doesn't care about the device

At about timestamp 4:13 it looks like the fuse would only blow if it is BEFORE the capacitor connection...??

Please can I use a x2 capacitor in series with an led at 230v ac for limiting current ?

@learnelectronics

Жыл бұрын

I'm sorry, I'm uncomfortable giving out advice regarding AC circuits.

Do what they do in China and blue dip your caps to make them Class Y ;).

Another good one, Paul. I always learn something from you.

How to know if X2 capacitor is not good?

If I understand it correctly, the safety capacitor is there purely to protect the user? No other purpose?

@learnelectronics

Жыл бұрын

Correct

💡Now I understand. Correct me if I'm wrong. If I were to replace the original safety capacitor with a higher voltage rated one, that would allow for higher transient voltage to enter my equipment and possibly damage the device. Replacement of a damaged safety capacitor should be the same capacitance value and voltage value then. ☮️ brother.

@learnelectronics

Жыл бұрын

You are correct sir.

@KissAnalog

Жыл бұрын

Actually no - the safety capacitor is double insulated so it can handle line surges. Higher rated voltage caps do not afford the same safety. Use an X1 instead of X2.

awesome! learned a bunch.

I was waiting for a video about safety caps, great thanks for making this video.👍👍

a question: I use the same capacitor with the same values. Which strong resistor value do you recommend to use? Based in your first schematic.

Nice i learned alot from this video

Errors concerning low voltage circuits, for example battery operated audio amplifiers, aren't very serious. Presentations dealing with line voltages demand more scrutiny and immediate correction.

It's often claimed that "Class X capacitors are designed to fail short and class Y capacitors are designed to fail open" but I think this is nonsense and I've never seen a manufacturer state this. Both class X and class Y capacitors are typically metallised film capacitors which are self healing and do not fail short circuit under normal conditions. They gradually degrade with reducing capacitance when subjected to over-voltage spikes. Class Y capacitors are designed for use in situations where their failure could lead to a risk of electric shock and so are required to withstand higher voltages without failure. The use of capacitors in common mode filters as described in the video does not present a risk of shock and so does not require class Y capacitors. An application which does require class Y capacitors is one where a capacitor is connected between the primary and secondary circuits in a switch mode converter. Short circuit failure of the capacitor could result in mains voltage being connected to the output. This is something that is often ignored in cheap Chinese electrical devices such as mobile phone chargers making them dangerous. The main feature of both class X and class Y capacitors is that they are designed and rated for direct connection across AC supply voltages. Note that the voltage rating shown on the case is always an AC value.

great video, thanks

Good video, good Information 👍

Don’t MOVs do the same thing?

How does this capacitor keep you safe?

@learnelectronics

Жыл бұрын

Are you shitting me? They are designed to fail in a way that won't cause damage. That was the entire point of the video.

What if we use this type of capacitors in 555 timer astable mode? Does is differ in function?

I have a question I have broken my capacitor of my compressor it is the ( mkp-x2 40/105/21 22 uf ) and now I want to order a new one but can't find the same one is it possible to get a replacement and if so which one can i order

Just used 32 of exactly that first model in a beefy little ioniser. Very annoying that they're built for PCB and have perfect pitching but the position of the case shifts by up to 3mm in all four direction.

great work bro very useful info.

I HAVE X2 AND X1Y2 CAPS THAT GO HOT TO GND AND NEUTRAL TO GND. I use them for Computer power strips all the time.

Really wish you would use a script. A lot of duplication of statements. Hard to follow, and sometimes, often you skim quickly over done of the most important details.

On voit plus ses doigts que les condensateurs lol