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Bunch of Relay Questions? Answered

Hey Guys

This will be my first relay project and I have a few questions regarding how to wire up a relay and such.....well there is not much to say, all the questions are in the diagram. So....yeah.




Best Answer 3 years ago

I Really Wish more people would outline a question like you have ! lol

Q1-A, Yes

Q1-B, works either way, but generally you want to turn the hot / live wire on and off to minimize the chance of electrocution. So Yes it should be wired how you described it

Q2, **DO NOT** use a breadboard for the AC section of your schematic. I like to use breakout boards like this. or just solder them to a custom PCB with larger holes. Screw terminals work well too.

Q 3&4...

Look at what the total current draw (Add 20% just to be safe) of whatever Device you are trying to switch on/off. Just buy a relay that can handle the Max Current

The Amp rating of your relay is the Maximum Rated Current. Using less Current then what it is rated for is ~ok~. Only real downside is higher rated Relays cost more and may need a higher gate voltage to turn on.

Q5, In Canada (and probably the US too) the black wire is hot and white is neutral. the (UK?) may be different. Buy a circuit tester just to be safe when you are working around Main's Electricity ! it should help you identify the live wire.

PS, Seems like this is one of your First 220 AC projects. Please Continue your research before you have your fun !

Some simple safety precautions like a Fuse or using a GFI could save your Equipment, not to mention your Life / General well-being :)


Answer 3 years ago

Reply to A1. Thanks

Reply to A2. Can i use the normal veroboard for this project?

Reply to A3. Whats the typical amount of Amps a lamp/fan use?

Reply to A5. I live in Paki :) I think I'll do some research, thanks ! :)

Oh and do you have skype? I wanna talk to you and ask you some stuff. If you do PM me your username


Answer 3 years ago

A1, No Prob !

A2, In a pinch it works; Just be sure no tracks have crossed. Hold the PCB up to a light and any crossed solder joints will be darker between the two tracks. I like to run a small knife between the tracks to be sure.

if the holes are too small you can solder the main's lines directly to the bottom of the Board.

A3, You have to look at the Device you are powering. There will be a sticker or label that will tell you how much each Device consumes; then add them together. Generally 10-15 Amp will work because that is what your breaker box / fuse panel should be rated at.

A5, Instructables has some good Examples. Look on the side of your page for some good Reference !

and yeah, I still don't have Skype. :'(

Feel free to send me a PM over Instructables anytime and I'll get a Email. Or just come back to the Answers Forum and the rest of the community could help you out at the same time !


3 years ago

Sounds more like we are doing the homework again...