Adding electrical service to basement

[xidsti]

I'm in the planning stages of finishing a room in my basement. The main panel for the house is 200A and is located in the basement. What I would like to do is add a second 200A panel just for the basement. The reason why I want to do a separate panel for the bsement (not a sub panel) is that at some point in the future we may want to move the washing machine and clothes dryer into the basement, possibly put a kitchen, and maybe a hottub. The house is 7 years old, and all electric w/ a heatpump. Initially the basement will be used to host LAN parties (parties where everyone brings their computers and has fun gaming against each other) for up to 30 people (30 computers and monitors).

Am I right that a sub-panel off the 200A main panel would not be the way to go?

Is it even possible to do something like this: Utility --->Meter------------- | | | | 200A 200A

Instead of this: Utility --->Meter ------200A ----- 100A

To accomplish that would I have to have 2 meters? (against zoning to have 2 meters on a single fam residence where I live.) Utility --->Meter--------Meter | | | | 200A 200A

Or would I have to do this? Utility --->Meter ------400A ----- 200A

Of course whatever I do will be done by a licensed electrician. Thanks in advance for any advice.

[Steve Barker]

If you're breaker panel is already in the basement, then all you need to do is add the circuits. You're not talking about that much additional current needs. And since your "moving" the washer and dryer, there's no more draw than you already have on those particular items.

[Doug Miller]

Why? You're only talking [below] about another 30 or 40 amps of load (the washer and dryer don't count -- that's not new load, just relocated load). What do you need with a second 200A panel?

So? That doesn't preclude installing a subpanel.

A subpanel is definitely the easiest and lowest-cost method of expanding the number of available circuits. I don't understand your reluctance to do this. Why would you want to add another main panel?

And of course you may not even need to do that, depending on the space available in your current panel.

[xidsti]

I'll have to look and see how much room is in my existing panel (not much if I remember right (4 or 6 slots at the bottom).

So it doesn't matter that 30 computers running at the same time will be using 75-150A by themselves? (my computer is using 2.5A idle, and

3.4A when playing games (550watt Power supply) and some of the people that will be gaming with me have beefier hardware (750-1000watt power supplies and dual video cards so 4A idle, 6-7A while playing)). Thank goodness for LCD monitors and their lower power requirements.

[gfretwell]

You can do the above. Just get a listed splicing device for the split in the service entrance conductors. The real problem is you are still limited by the service drop and SE conductors so if you don't "heavy up" you will still be limited to 200a of main breaker total. Your panel may have "feed through lug kit" that will allow you to feed a second panel off of the rails on the load side of the main. That will be a sub panel tho (4 wire feeder "tap")

[Doug Miller]

With respect to whether you need a subpanel or a main panel, no, it doesn't matter. The electrons can't tell what kind of panel they flow through.

Have you verified those numbers with a clamp-on ammeter, or are you just extrapolating from the power supply rating?

[Steve Barker]

I'll bet if a guy actually measured the amps being used by a computer, it would be a lot less. You have to remember that just because you have a

550watt PS, doesn't mean it using all that. Just like welders never use anywhere near the power the plates say they do.

[xidsti]

Turns out I have 3 blanks at the top: photo -

Does this mean having 2 - 200A panels coming from the meter is still only 200A of power available (the second panel NOT a sub-panel of the first)?

I dont have a clamp on ammeter (wish I did). I basing it on this from my battery backup:

I guestimated the amperage based on idle and what that screen reports when I close a game (around 340watts, but i can't screen shot before it starts dropping) and dividing by 10 (Turns out the formula is watts/ volts=amps, so 2.2A at idle and 3.0A when playing?). My monitor (lcd) is plugged into the same battery backup, so that load is for CPU and monitor.

[xidsti]

Yeah... 550w theoretically would be 550/110=5A

[w_tom]

How can he do that and still meet code requirements that want all electricity to a 'unit' cut off at one box? What would permit an exception? Two mains boxes serving the same living unit would violate code requirements.

[gfretwell]

You can have up to 6 "grouped" disconnects. If the panels are next to each other that is "grouped". This is a very common installation in a commercial setting. They also do this with 320 and 400a services in large homes. They will often install two 200a panels with two discconects but you still need the service drop, meter and SE cables sized to the total load.

[HeyBub]

So get one. About $17 from Harbor Freight. Also get a Kill-A-Watt: a plug-in power monitor (voltage, amps, KW, KWH, etc.). About $25 on Ebay.

[Doug Miller]

The amount of power you have available is limited by the size and number of the service conductors coming from the power company's transformer to your meter. You have 200A service right now. Unless you add another service (increase the number of service conductors) or upgrade the existing service to

300A or 400A (increase the size of the service conductors), you're never going to get more than 200 amps, no matter how many panels or what type of panels you install.

Get one. That computer probably isn't drawing anywhere near as much power as you think it is.

[xidsti]

Thanks for all the comments! I definately have a better idea of what I'm going to watch out for.... now off to ebay to get an ammeter! Thanks again!

[w_tom]

I thought those 'groups' had to service separate sections of a building. And I thought that grouping could only be in a same residence when each box serviced a different residential unit. Perchance, anyone remember the article number?

[Goedjn]

Worth asking, but most of the rules I've looked at don't start with the special rules until you get to at least 50. He's more likely to run into zoning problems than building code issues.

30 doesn't even get you to the point where you need additional/wider exits according to this document from NY.state.

[Bud--]

Nope, nope and 230.71

-- bud--

[gfretwell]

Nope. The easiest example is the "split bus" panel where there is one disconnect for all the 120v breakers and separate disconnects for the

240v loads. The 240v loads are all service disconnects. As long as all power is off with 6 throws or less you are legal. The 200a panel deal on 400a services is very common with 2 disconnects. It saves the installer a lot of money over the cost of 400a equipment and gives you 84 possible breaker slots vs the max of 42 you can have in one panel

[gfretwell]

BTW look at the bright side, you get to sell them 2 polyphasers

[Tazz]

But when you are tryin to calculate a load for sizing a service you have to go off nameplates. Worse case scenario everything all comes on at once it needs to be able to handle it all.