My power source arrived today. It looks pretty cool. It has a pot to adjust outgoing DC volts. Where the AC comes in there a ground symbol, an N and an L. Can anyone tell me does the hot wire connect to the N or the L? There were no papers or instructions.
Kinda dumb that it didn't come with at least some wiring instructions (/-
Anyway the "Hot" should be the "L" or "live" if our terminology is synchronized. Alternately the N terminal goes to the wider blade/slot of your electrical plug, the skinnier blade/slot goes to the L, and obviously the ground pin goes to the ground terminal+case. However, it will prolly work with N and L wires switched unless you have the neutral wire in your house grounded, then it *MAY* trip a breaker. It may also freak out your GFCI breaker if you have it wrong. Unless something is somehow way non standard, then it's not going to be critical.
Now if your not sure and you want to test it... and this is not the safest thing, but it's my tried and true method for testing things when I don't fully trust them. Wire it up the way you think is best with as many circuit protections as you can cram in
*OBVIOUSLY NOT WHILE IT'S PLUGGED IN*, Stand way back and plug it in; then quickly pull it back out in one quick motion, not even trying to run the device. Do this while being careful to touch only plastic. If there is a problem it will trip one of the several layers of protection or give you some indications that it's going to. If not. . . plug it in for longer and longer each time. Alternately you can use the switch on a power strip instead of plugging it in and pulling it back out. It should be obvious that things are good when you reach < 5 seconds and nothing bad happens. Do this at your own risk though, and use common sense not to touch anything electrically conductive and so on. You may want a fire extinguisher and a helping hand that knows CPR near by too. (very unlikely to actually need them.) A freshly electrocuted healthy person can almost always be saved with the proper application of CPR.
Low voltage panel mount breakers. Something like these?
**broken link removed**
I'm thinking that's what hes saying. They use them in serge protectors/power strips. I have a few of the individual units too. They are usually for use at = or < 10A (and of course < 120v.) The advantages to these devices is that they can blow more than once and you can reset the circuit quicker when it happens. I'm not sure if they trip faster than fuses blow, on the contrary it seems that my power strip takes quite a while to trip when I over load it.
If I hooked the power supply to a jack to fit the connector on the pump, could I use my multimeter to determine how much amperage it draws and use that to determine the best size for a fuse?
Not with your average multimeter, no. You would need to sample the starting conditions 100's of times for each and every pump using a shunt based
ampere meter and a peek detector. Then do a statistical analysis on the resulting data to figure out exactly what fuse rating would be ideal. It's easier and close enough to just guess then use trial and error. 5 amps per pump is my educated guess for a decent fuse rating, going on the safe side of course. Keep reading. . .
I don't want to further complicate things. I was just wondering if a fuse was going to be installed to protect each pump, could the fuse simply be replaced by a reset button. Shoot, unless something got stuck in the pump I can't imagining blowing a fuse. Plus the pumps have a cover so nothing large can get in. A fuse is plenty. But thanks anyway for that link 4pyros.
Yeah, fuses are cheaper and easier to come by anyway. And under normal operation your not going to blow what ever is installed. Even if you do your not going to want to be able to just "flip a switch" back to the on position right away, because if it does blow out something is almost definitely wrong and needs inspection and retesting before you power things back on for real.
If it were my choice, I would use INSULATED female quick connect terminals and car fuses (the slot style, not the glass tube style). You can normally get both items at even the smallest of hardware stores, for less than $10 total. These fuses are closer rateing to the voltages we are using in this project also. Plus in one trip and for the same price you can get an assortment of sizes to fine tune the over current "blow out" point. Id say five amps per pump (orange color normally) is a good fuse size starting point. I wouldn't go over 15 amps per pump, or there is no point in having fuses at all.
Do note also that fuses are typically installed to protect from *FIRE* and not meant to protect one from electrocution (including your aquatic inhabitants). GFCI breakers as well as other techniques are for protecting one from electric shock. Also, both fuses and breakers have a 50/50 chance of protecting the up stream system from permanent damage caused by down stream failure. Note though that this is not really the intended purpose, just a common consequence of their use. You shouldn't rely on it, a fuse for the whole controller should be installed for this reason. About 15~20 amps should do. For this connection you could use one of the mini breakers instead if you really want to.
Finally when your building this circuit, if any thing blows right away, suspect wrong wiring first. After you CAREFULLY inspect things and it seems good, THEN you can up the protection devices rating by 5 amps. If it still blows/trips the protections then AGAIN check the wiring, ONLY BETTER THIS TIME. Only after you have exhausted all these things should you suspect faulty parts. I wire at least one thing backwards just about every time I make a circuit, comes with the territory.
Until next time. . .