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Author Topic: Separate Breakers  (Read 13235 times)

Jonathan Johnson

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Re: Separate Breakers
« Reply #20 on: January 31, 2014, 01:18:18 am »

Another pet peeve-being asked to bid a job "wired to code".  No ones gonna be happy with it-but if I bid it wired like it should be, I ain't gonna wire it.... design/build + competitive bidding makes life rough for sound providers.

I used to live in a tract home, built in 2003. Code requires a 15A circuit in the garage. The inrush current of many power tools is greater than 15A... whenever I was doing woodworking in there, I often had to reset the breaker after trying to turn on a saw or air compressor or something of that nature. Most of the time it didn't overload, but many times it did. Quite annoying, when for less than a hundred bucks (on a $170,000 home) the whole problem could have been avoided by installing a 20A circuit. Rewiring it wasn't much of an option because the walls were already finished. And the crazy thing is, it wasn't wired by the cheapest electrician in town.
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Mike Sokol

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Re: Separate Breakers
« Reply #21 on: January 31, 2014, 07:12:02 am »

I like Mike's pulsating load idea-might come in handy identifying which neutral wire goes to which circuit in that j-box, too.

This "Pulsar" is a pretty handy gadget to have around for troubleshooting all kinds of "current" issues including neutral current paths. I'll see if I can find a cheap source of timer-relays and build one again. Also, an analog meter is best for this type of troubleshooting, or at least a digital meter with an analog bar scale. It's really hard to read a pulsing current on a digital display that may only update a few times a second. I did this originally nearly 40 years with a Triplett analog clamp meter, and Amprobe still makes the RS-3 analog meter.   
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Stephen Swaffer

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Re: Separate Breakers
« Reply #22 on: January 31, 2014, 10:11:21 pm »

The inrush current of many power tools is greater than 15A...

It is not uncommon for inrush to be 2 to 3 times FLA-so a so a half horse motor pulling 9.8 A can pull 20 to 30 amps on start up.  #14 wire has a resistance of roughly 3 ohms/1000 feet.  50 feet of NM=100 feet of wire or .3 ohms times 30 amps =9 volts drop which means the motor will start harder and pull even more amps as well as take longer to start which often equals a tripped breaker.  The 15 A breaker MIGHT have held if they had used #12.  Voltage drop is always the worst on a circuit when it is working the hardest-which is when it is most harmful-be it a power or speaker circuit.

I ran across a home built in the 90's with the range circuit wired with #12 NM, on the opposite corner of the house from the panel across an 90% finished basement.  Yes the right wire would have cost more-but nothing close to my quote to fix it-which was deemed too pricey.  Far better to plan and do it right the first time, but I find it very difficult to get owners/managers that are not familiar with electricity to stop and think about what they might or likely will do in a space in the future. 
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Jonathan Johnson

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Re: Separate Breakers
« Reply #23 on: February 02, 2014, 10:43:29 pm »

This "Pulsar" is a pretty handy gadget to have around for troubleshooting all kinds of "current" issues including neutral current paths. I'll see if I can find a cheap source of timer-relays and build one again. Also, an analog meter is best for this type of troubleshooting, or at least a digital meter with an analog bar scale. It's really hard to read a pulsing current on a digital display that may only update a few times a second. I did this originally nearly 40 years with a Triplett analog clamp meter, and Amprobe still makes the RS-3 analog meter.

Such tools and tests do require the technician have the ability to interpret the results, based on what would be expected on a properly wired and functioning circuit, the expected results from different possible fault conditions, and a fair amount of intuition. There is no magic tool with a green light indicating "all OK" and a red light indicating "something's wrong." Even a basic pass/fail cable tester can falsely indicate a pass where a fault exists.
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Mike Sokol

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Re: Separate Breakers
« Reply #24 on: February 05, 2014, 10:56:38 am »

Such tools and tests do require the technician have the ability to interpret the results, based on what would be expected on a properly wired and functioning circuit, the expected results from different possible fault conditions, and a fair amount of intuition. There is no magic tool with a green light indicating "all OK" and a red light indicating "something's wrong." Even a basic pass/fail cable tester can falsely indicate a pass where a fault exists.

A few years ago I started drawing circuit diagrams of how power is hooked up and distributed, just to get my mind wrapped around how to test for strange problems. Here's one that shows the basic connections. I made another diagram somewhere that includes typical series resistance you might find in the wiring so I can calculate expected voltage drops with typical loads. I'll post that one later once I find it in my archives. 
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Frank DeWitt

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Re: Separate Breakers
« Reply #25 on: February 05, 2014, 12:41:12 pm »

It is interesting how wiring needs change.  I designed and built my house 25 years ago.  At the time I way over wired it.  All 20 amp #12  different circuit for each bedroom ETC.  I ran 2 ckts to each counter in the kitchen (Total 4) plus one for microwave, one for frig, and one for lights, and one for dish washer.  Now 7 is the minimum code for a kitchen.  I put only one outlet in each bathroom because why would you want more, plus power in a bathroom can be dangerous.  Last week I added two more duplex outlets to one bathroom and one more to the other.  (I didn't see electric tooth brushes or electric towel heaters cumming. 

My point,  It is quite hard to over wire a house, and now I understand why most old houses seem under wired.

BTW When I bought my first house it had one outlet in each room down stairs and one light (no outlets) in each room upstairs. All on a 30 amp service  15 down, and 15 up.
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Jonathan Johnson

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Re: Separate Breakers
« Reply #26 on: February 05, 2014, 04:49:58 pm »

I designed and built my house 25 years ago.  At the time I way over wired it...  Last week I added two more duplex outlets to one bathroom and one more to the other.  (I didn't see electric tooth brushes or electric towel heaters coming.)

My point,  It is quite hard to over wire a house, and now I understand why most old houses seem under wired.

In residential wiring, code requires that no spot along a section of usable wall (the fixed portion of a sliding door counts as wall) be more than 6 feet from a receptacle. This rule is often misinterpreted that outlets can't be more than 6 feet apart, but a strict reading of the rule reveals the spacing is actually 12 feet (but limits to 6 feet from the end of the wall). The purpose of this rule is to reduce or eliminate the use of extension cords and to prevent cords running across doorways.

The spacing of outlets is probably still adequate, but only putting a duplex receptacle at each location isn't. On each side of our bed, my wife and I have power strips with several things plugged in: bedside lamp, clock radio, & cell phone charger on each side. If there was a quad receptacle (two duplex in a 2-gang box) on each side of the bed, the power strip would be unnecessary. I think that will become a new standard due to the proliferation of electronic devices: quadplex receptacles throughout the house.

On a side note, when a customer of mine is remodeling an office, I tell them to put network drops in every possible location they may need one, then double it. (Consider that each desk may have a PC, a phone, and a printer all wanting to connect to the network!) It's much cheaper to overwire when the walls are open than to add wiring later. I've had many customers who've ended up using the extra wire.
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Jonathan Johnson

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Re: Separate Breakers
« Reply #27 on: February 05, 2014, 04:55:59 pm »

I ran across a home built in the 90's with the range circuit wired with #12 NM, on the opposite corner of the house from the panel across an 90% finished basement.  Yes the right wire would have cost more-but nothing close to my quote to fix it-which was deemed too pricey.  Far better to plan and do it right the first time, but I find it very difficult to get owners/managers that are not familiar with electricity to stop and think about what they might or likely will do in a space in the future.

Using too small of wire for a large load is like using a garden hose to put out a house fire. It's not going to do the job and something's going to burn.

The larger the load, the larger the wire needed; just like the larger the fire, the larger the hose you're going to need.
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Frank DeWitt

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Re: Separate Breakers
« Reply #28 on: February 05, 2014, 06:00:36 pm »

If there was a quad receptacle (two duplex in a 2-gang box) on each side of the bed, the power strip would be unnecessary. I think that will become a new standard due to the proliferation of electronic devices: quadplex receptacles throughout the house.

On a side note, when a customer of mine is remodeling an office, I tell them to put network drops in every possible location they may need one, then double it. (Consider that each desk may have a PC, a phone, and a printer all wanting to connect to the network!) It's much cheaper to overwire when the walls are open than to add wiring later. I've had many customers who've ended up using the extra wire.

I saw that one coming  6 outlets om my side and 4 on my wife side and a 25 pr phone cable to the basement from one side. 

We have a rule at church  any time we pull any wire not in conduit, we pull a extra CAT 5 with it.  if we are pulling CAT5 we also pull an extra.  These days you can run anything on CAT5   data, audio, HDMI video, etc.  There is even a company that runs HDMI AND power so you can put a wide screen at the end of just a CAT5
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Stephen Swaffer

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Re: Separate Breakers
« Reply #29 on: February 05, 2014, 06:37:11 pm »

Leviton makes a TR duplex that includes 2 usb charging ports and fits in a single gang box.  Not cheap-but cheaper than having an electrician add another gang-and a lot less painless if it just a "honey do: project, too!
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