JDMCQ's Garage

no

 

How was ya'll day??

 

Saw a video with Britneys spears circa 2001... too bad she turned crazy!!!

 

not too shabby, that was until a Canadian said "ya'll"... you should be ashamed of yourself.

 

I was addressing the 'Muricans

 

I'll allow it... this time.

 

Hey

You guy

I have an electrician question for ya

 

go on

 

"listens" I like electricity... But hate it too.

 

Voltages coming into a main residential breaker are usually in the 115-120v ranges right??

Edit: And there are supposed to be NO breaker bypasses??

 

It's the bane of my professional career, I'm trying to learn about it.

 

from each line to ground, yes (typically closer to 120v). voltage across the lines should be ~240v.

what do you mean by "breaker bypass"?

 

120v for normal... 240v for large appliances. And I think everything is supposed to go through a breaker... Except maybe a sub pump may have a straight tap?

 

no, all circuits must have overcurrent protection. the breaker is there to protect the conductors, not the load.

 

So every house has 2 power lines coming in, 1 at 120v, and 1 at 240v?

I mean theres no reason that lighting circuits would bypass the main breaker. All lights are usually on individual branch circuits?

Basically I'm trying to figure out if a power surge would blow out all the light bulbs in a house before a breaker box could trip.

 

there are 2 "hot" conductors going in to each house, 180 degrees out of phase from each other. 120V from each hot conductor to ground, and 240V between the 2 hot conductors.

a power surge is a spike in the voltage. nearly all equipment requires a voltage within 10% of the rating to function properly. when the voltage spikes each piece of equipment will draw less current (ohms law), so it is entirely possible for the equipment/lights to fry before the breaker trips.

 

Aahh.. So basically two-phase power. We work with 3-phase on the large motors here so I understand the basic concepts of it. 3 live lines in each at 120 degrees from each other.

 

you got it. although you will want to avoid saying "two phase" around electricians, single phase is the proper term.

two phase does exist, sort of. in big apartment buildings they have a 3 phase supply, each unit taps off of 2 phases. their dryer and range have to be rated for 208V.

 

Why are commercial areas made 208v veresus 240v?