Residentail electric questions

[*hac]

A couple of quick questions.
1. What is the best way to isolate the netural bar in a sub-panel?
2. I am wiring a 1000' basement and want to know how many circuts I need.
3. What is the maximum number of can lights that I can put on a particular circut? I think the answer is that there is no limit. However, I want to make sure that I understand. I have 10 cans with 75W bulbs. I have a 15A circut. 15aX120V=1,800W. 1,800W/75W is 24. Therefore, the 10 cans that I want to install is ok?
4. How many watts should I "dedicate" to a general use recipitcal when calculating the maximum number per circut?

[*Wgoodrich]

The NEC is very specific in wiring design. However in the International Residential Code the wiring design is very generically worded. The wiring design is actually the same in the IRC versus the NEC yet in the IRC the wording is much more loosely worded and not so clear. The IRC also states that where the IRC differs from the NEC the NEC shall pervail. Then you need to check your local and state laws which ever adopts the electrical code as rules of law how they word it. Normally the NEC overrides or completes the rules in the IRC.

In the IRC it is required that you load the general lighting branch circuit no more than 100% of the amp rating of the wire and breaker serving that general lighting branch circuit. When dealing with incandescent lights it is easy just add up the watt rating of the light bulbs on that circuit and make sure it does not exceed 2400 watts for 20 amp 120 volt circuit or 1800 watts for 15 amp 120 volt circuit.

If you have 10 light bulbs rated 75 watts each your have a connected load of 750 watts. This is far below a 15 or 20 amp branch circuit. In fact you could intermix mix many receptacle on with that same branch circuit if you like. If you intermix light fixtures and receptacles it would be easiest to calculate as a commercial designed multioutlet branch circuit allowing for 180 watts per receptacle. Then you could take the 20 amp 2400 watt branch circuit and subtract the 750 watts total connected load of the incandescent light bulbs. This would leave you 1650 watts left on that circuit to use then you could divide that 1650 watts left by 180 watts per receptacle and you would find that you could add 9 receptacles to that same lighting branch circuit and still be well within the NEC and IRC minimum safety perimeters.

I know this is confusing but the above is working within the rules. If I actually quoted the rules that apply you would really be confused and I would have sore fingers.

The actual rule says in both IRC and NEC that you may load a general lighting branch circuit no more than 100% on a 20 amp branch circuit that would be 24 - 100 watt bulbs and add receptacles onto that branch circuit evenly amoung all general lighting branch circuits. If you did this you would turn on your 24 - 100 watt light bulbs and plug in a vacuum cleaner and pop the breaker everytime and still be within Code minimum standards.

I suggest you design as discribed at the beginning of this reply allowing for adding all the watt bulbs used on that circuit then divide the remaining watts left at 100% by the 180 watts per receptacle. Then you should be fine.

Hope this helps

Wg