120/240 Volt Power and Cockpit Safety!!!

[blueskydriver]

Here is a topic that I've seen no discussions on the subject (after searching):

Note: This is long, but good reading.

120/240 Volt Power Sources for your Cockpit and the Safety of it's use.

So, here are some questions that you might want to answer about your cockpit. Which cockpit will I build? Where is it located? How many power outlets do you have versus how many you need? What are the total amps/watts you need?

1. Either big or small, cockpits require raw power, do you know how much power in either amps or watts you'll be using? If you don't know this, start looking at every device you have (computer, monitor, I/O cards with seperate power supplies-know as wall warts) and read the labels. You'll either find watts or amps on them. Add all that info up, you'll then have a good estimate. Add at least 20% more to that number, if not more...for future expansion.

2. Where is the cockpit loacted? Garage, Bedroom, Apartment Living Room, or seperate out building? In any of these cases, you'll likely have 15-30 Amp outlets. Mostly you'll find 15 Amps, but if you're lucky, it'll be 30 Amp. However, I would bet anything that the circuits are being shared somewhere else already. How many times have you tripped the circuit breakers when someone else turns on a light in another room while your cockpit is all turned on? The point is, if you're sharing the circuit, that leaves you with less Amps/Watts avalable for your cockpit, and if your cockpit is not close enough to the outlet(s) where you're using extension cords and power strips, you'll have even more problems with the Amps/Watts.

Extension cords are usually meant for a specific use and those power strips you're using might be surge protected, but they're limited in Amps like the cords. You'll find that a lot of power strips are only rated for 15 Amps.

3. Do you know how to calculate your power needs? If not, here is a quick way: If you know the Total Watts then divide by the Voltage being used to find the Amps, in example 1200 watts divide by 120 volts equals 10 Amps. If you know the Amps, you then multiply by the Volts to get Watts.

Here is something you need to consider. In the US, the typical home has a 200 Amp Main Circuit Breaker for the entire house. So, if your cockpit project has 8 computers; 6 monitors in the MIP (B737 example 2-PD/ND, 1-Upper EICAS, 1-Lower EICAS, 2-CDU's); Powered USB Hubs; Extra PSU for the MIP, Overhead, Ped; and the Wall Warts for the MCP/EFIS units. How much do you think that is in power requirement that you'll need/use? If you say, "I'm just doing a C172 with one computer, monitor and some units like GoFlight stuff (that you'll likely use some USB Hubs for) on one outlet that I think is a 15 Amp circuit"

Well, what if your computer is the latest greatest 1000 WATT Powered Unit, with a 2 Amp Monitor and a USB Unit that draws .05 Amps, will your 15 Amp circuit support it? What if your room, say living or bedroom also has a TV, stereo, cell phone charger, two lamps, and cordless phone all on the same circuit, but plugged into different outlets? Now will you have enough on that same 15 Amp circuit?

Of course you might say "I don't know" or that "the entire 15 Amps (or the entire 200 Amps) is not likely to be used all at once", but if you're sharing outlets on one 15 Amp circuit, as I mentioned, do you think the continous use is now higher? 200 Amp total does not matter, it's the individual circuit Amps total that is important. And, how about those extension cords/power strips, if you're really sucking the power, how long before they start melting from heat?

Take this from lessons learned, melting extension cord ends or power strip outlets is very scary because unless the hot (black) and the netural (white) arc with each other or the ground (usually green), and thereby tripping the breaker, the cords, strips will melt and catch fire long before the arcing occurs.

Here is a sure sign that you got problems, look at any power strips and if you see any discoloration on that strip from heat (look for yellow or brown staining), or feel those cords and wall warts, if they're too hot to touch, you got serious issues! STOP what you're doing and rethink your power usage/needs. Also, unplug and avoid any extension cords and move closer to the wall outlet(s).

I am no electrician, but you should either call one or get an electrical book to understand this more! Why? Well, if you set your house or apartment on fire because you're doing something in it that it's not designed to do, you'll be at fault, and your insurance company will blame you for neglectful acts and not pay after your place is in smoldering ruins...

However, there is hope! Ask an electrician about your cockpit and he can help you get all the power you need by adding circuits, outlets, sub-panels, etc, etc. Thus, you can still have fun, but you'll be safe while doing it!

[fordgt40]

An excellent article and timely reminder to all of us. I would just add the need to ensure that all supplies are adequately fused, including the low voltage supplies to backlighting etc. It is surprising how much current can be drawn over low voltage circuits. You should not have circumstances whereby plugs/wires get distorted by heat without tripping a breaker or blowing a fuse. Correctly rated fuses should be there to protect the wiring from carrying an excessive load

David

[737NUT]

I have a good and easy solution to your concerns to protect yourself from shock but first a little history. Back in to 30's thru the 70's allot if not most appliances were made of metal which posed a shock hazard if something came apart inside. Now days all the stuff is plastic and pretty much no skock hazard. Hence th 3prong plug is disapearing from appliances,tv's etc: If you were to look carefully in your home electrical power panel, you would see Neutral (white) and Ground (green) tied together! Both are the gnd plane.

Here is what i did in my real cockpit when i had one to protect my children, guest and myself from shock. VERY VERY simple. I wired up two 20amp gfi outlets on the sim with a on/off switch with indicator light. Everything ran off these 2 outlets, mind you i had 120Vac 400Hz, 60Hz and all DC power sharing the cockpit shell as the ground plane. I had 8+ computers, God knows how many power supplies, plus USB's. NEVER had any heat or power drop issues. I sacraficed myself to test the GFI circuit, i purposely touched the 400Hz and GNd with my body, not even a little tingle!! GFI tripped instantly! Take your worries away, wire it all thru a properly rated and installed GFI and you will be good to go. I would say its a safe bet that a single 20amp circiut will run 99.99% of the sim's built by people on this site. My new home is getting a single dedicated 20amp circuit for my new sim..