Makes Any Sense?

Mike Finley

Regarding electrical - say for doing a deck or something you need electrical power and you plug into the house for it. Is there any advantage to running a large gauge wire to 1 interior outlet, say 8 gauge wire, and having say 6 outlets on this wire and plugging 6 things into it. Vs plugging all 6 of those items into 6 different outlets in the house but all on the same circuit? I'm being told that there is a difference between the two with the former being advantageous to the latter.

mdshunk

It's about a wash either way. Using one really heavy cord to a spider box or using somewhat lighter cords from many receptacles on the same circuit to individual tools is about the same voltage drop. Plugging into multiple receptacles might be the better idea, since at least a few of them will be on different circuits.

If you plug in indoors, pick receptacles that are likely to be 20 amp dedicated or semi dedicated receptacles. Examples include: the washer receptacle, the sump pump receptacle, the kitchen counter receptacles, the bathroom receptacle. Running a heavy gauge cord is always an advantage, due to the fact that there's less voltage drop. No self respecting contractor's cord for anything should ever be less than 12 gauge, and longer ones that lead to your spider boxes should be at least 10 gauge.

Mike Finley

Thanks MD, I met a guy who swears he doesn't pop breakers because of his heavy wired spider box, didn't make sense to me but I thought I would ask.

Is it true that not using beefy enough electrical extension cords can actually prematurely age a motor in a saw? Or do they have them built well enough that that's not true anymore?

mdshunk

Well, low voltage is a generalized killer of anything with an AC motor. I suspect that motors are bulit better now, but maybe not. Having a heavy cord will benefit you. Plus, with voltage drop from using too light of a cord for too long a distance, your saw WILL spin slower. This may effect the quality of your cut, and will cause more blade binding and bogging. Here's a quick chart I whipped up, based upon a 12 amp circular saw. Assuming the voltage starts out at 120 at the temporary service or generator, here's what long cords of various gauges do to the voltage (assuming a 12 amp load on the end):

#16 cord, 25 feet 117.4V, 50 feet 114.8V, 100 feet 109.7V, 200 feet 99.3V

#14 cord, 25 feet 118.4V, 50 feet 116.9V, 100 feet 113.7V, 200 feet 107.4V

#12 cord, 25 feet 119V, 50 feet 118V, 100 feet 116V, 200 feet 112.1V

#10 cord, 25 feet 119.4V, 50 feet 118.8V, 100 feet 117.5V, 200 feet 115V

#8 cord, 25 feet 119.6V, 50 feet 119.2V, 100 feet 118.4V, 200 feet 116.9V

You can see from this chart that running heavier cords, particularly for longer distances, will pay off. This might explain why a carpenter may think his saw is junk or wearing out, but you'll often notice that he's got 5 zillion feet of orange #16 cord running to it. The saw might be fine, but it's not getting near enough voltage due to the long lead.

The guy with the heavy wired spider box probably does pop breakers less often, since his tools are getting the full voltage and will not bind nearly as often (which is usually when the breaker pops). Plus, air compressors will start much more easily at full voltage. Low voltage when the air compressor goes to start is another popular thing that blows breakers. Using either a heavy dedicated extension cord OR a very heavy gauge lead on the spider box will accomplish the same thing. I might whip up another chart later on that shows what low voltage does to increase amp draw. It's equally as dramatic. I'm all calcualted out at the moment.

Hey, this sounds like a good article topic for Nathan. Maybe I should expand on this. Everyone uses GFCI cords, right? I promise not to tell, OSHA's not looking.

Mike Finley

You are a wealth of knowledge man. I'd swear you are half electrician/half electrical engineer from some of the stuff you write here!

mdshunk

No, I just wanted to give as complete of an answer as I knew how. Actually I'm 1/4 electrician, 1/4 prick, 1/4 husband, 1/4 daddy.

mdshunk

If you're doing a longer term project, you can build (or have your electrician build) a spider box with a small panel on it that you can plug into the 4 wire range or dryer receptacle. When I build temporary services for certain contractors who who such home made panel setups, I just install one 50 amp 240/120 grounded receptacle on the temporary pole. They keep their panel thing-a-ma-jig in the house or on their job trailer, and wheel it into place when they show up in the mornings. This keeps the breaker nearby for resetting, and keeps people on jobs nearby from stealing their temporary power. One guy has his setup permanently mounted on a hand truck.



This wouldn't make sense for a deck job, for for a big addition or a big rehab, it's a popular thing to use. Some guys call these "dog and pony show panels", since portable panels with receptacles like this one are often used at convention centers and trade shows.

The spider box below is a premanufactured one, most often found scattered about on larger commercial jobs, and normally features receptacles of various amperages and configurations.

bob the builder

MD I have a ? that relates to topic

I have a 120 amp distro. box I use for running a sound system. On the older houses where the wiring is older than me could I connect an aligator clamp to each leg, where service connects to house, typically near the soffit and before the ceramic insulator, then make my own earth ground?

mdshunk

Could you? Yes.
Would it be safe? No.
Would it be code compliant? No.
Would it be legal? No, you'd be stealing unmetered power.

bob the builder

Yeah I tryed. There is this place in particular I run sound at and it is about a 400 foot run outdoor venue and we always overload the circuits. I would be saving about a hundred feet doing it the way I mentioned.

Mike Finley

Wow, now that sounds like an idea just full of potential, I have never heard anybody mention anything like that before.

So give me some details because this sounds really promising.

10/4 wire? Say about 50 feet or would that get too bulky? What would you do to make it easily work with 3 wire dryer set ups and 4 wire set ups? Have a 4 wire and a 3 wire plug attached to it?

It would end up being 110 of course right, so you would have what 2 circuits on the spider box? One inline GFCI breaker where the wire enters the spider box?

mdshunk

This would only work with 4 wire range or dryer receptacles, since the 3 wire ones are ungrounded. For a dryer, you'd need 10-4 cord, like SO cord or SJO cord. For a range, you'd need 6-4 cord. Naturally, install the matching cord cap on the end. The other end of the cord would terminate in a small panel, setup as a subpanel with the grounds and neutrals isolated on seperate bars. Then, you'd install branch circuit breakers in this small panel to correspond with each receptacle that you mount on, near, or under the panel. It is imperitive that anything plugged into a range or dryer receptacle go to a small panel, with 15 or 20 amp breakers. Do not run normal receptacle straight off a range or dryer receptacle, because they will be sorely overfused. Think fire, death, havoc, destruction.

Resist the urge to do this with a 3 wire setup, since there is no ground, and DO NOT install two cord caps, since you'll have hot prongs hanging exposed when you're using the other one.

The other option is to have no cord cap at all, and install a 30 amp double pole breaker in the home's panel and connect this cord directly to the panel temporarily. That's not exactly compliant, but guys do it.