Extension cord question

[TNhobbyfarmer]

I have a job to do that will require a hammer drill. The only such drill I own is electric, 7.5 amp. The job is located about 130 ft. from the nearest plug. The only extension cords I have are the cheap 50 ft 14 gauge type. Couple of questions. 1) How much power will I lose using this type setup? 2) Will I potentially do damage to the drill?

 

[Diggin It]

How big of a job? How many holes? What diameter? In what .. block or poured concrete?

 

[Bigfoot62]

The old rule of thumb for voltage drop is: You go up one size for every 100'.

14 gauge is rated for 15 amps, IIRC, so 130' shouldn't reduce the current enough to hurt a 7.5 amp motor.


My only other observation is that you could use this as an excuse to get you wife to buy you a new cordless drill. I have the DeWalt 20v MAX. They're great!

 

[RalphVa]

I'd be inclined to not only rent a more hefty and longer extension cord but maybe also a more powerful hammer drill. I needed to drill holes in our concrete decking to install a safety pool cover for the winter. Tried with the little hammer drill about like the one you have on a hole or two. Took absolutely forever.

Went out and rented a big drill. Brrriittt! Hole done. Kept repeating. Must have done all the rest in way less time it took me on the 2 holes I tried with my little hammer drill.

Ralph

 

[TNhobbyfarmer]

How big of a job? How many holes? What diameter? In what .. block or poured concrete?

Small job. Four 1/2" holes in block.

 

[Bigfoot62]

Small job. Four 1/2" holes in block.

Now, Diggin' It will probably want to know what color are the blocks? :laughing:

 

[Diggin It]

I'd consider buying a cordless hammer drill from HF or Northern. I think they have some in the sub $100 range. Should knock those four holes out in less than one battery charge.

 

[PILOON]

Shucks, but 100 ft 12 g extension and be done.
Charge 1/2 the cost to the client if that makes you feel better.

 

[randy41]

Shucks, but 100 ft 12 g extension and be done.
Charge 1/2 the cost to the client if that makes you feel better.

and a 30’ bit

 

[Sawyer Rob]

Now, Diggin' It will probably want to know what color are the blocks? :laughing:

ha ha ha

 

[Diggin It]

and a 30’ bit

That's a bit of a stretch.

 

[Slowpoke Slim]

Do you have a generator?

Probably not, since you don't even own a proper extension cord.

:laughing:

 

[Industrial Toys]

14 gauge is the same as the wiring in your house and it's not hard to get a long run. I try and plug in as close to the panel as possible, so it's less of a cumulative drop.

 

[EddieWalker]

Go for it, you'll never notice anything.

 

[TNhobbyfarmer]

Shucks, but 100 ft 12 g extension and be done.
Charge 1/2 the cost to the client if that makes you feel better.

Not a job for someone else. No client to charge. Just a personal job at my house.

 

[John_Mc]

14 gauge is the same as the wiring in your house and it's not hard to get a long run. I try and plug in as close to the panel as possible, so it's less of a cumulative drop.

My house is all 12 gauge. It was built in 2001/2002. I know some older houses around here have smaller gauge wire.

 

[Industrial Toys]

12 gauge is nice, but having worked as an electrical apprentice for years, I would not have liked to wire a house with 12 AWG. I WILL run it for outdoor HD outlets, simply to cut down on voltage drop, for this exact reason of plugging in a cord and having further drop.

 

[John_Mc]

130 foot run with 14 gauge COPPER wire, 120 volts @ 7.5 amps would result in almost 5 volts drop. If you are feeding it with an ACTUAL 120 volts, you are probably fine. your drill should run on 115 V just fine. If you are feeding it with 110v, the drop could be a problem. Pay attention if your drill start running hot. Stop and let it cool down. Wait a bit between holes to let the motor cool. If your extension cord is aluminum (or CCA - Copper Clad Aluminum), the voltage drop will be even more.

7.5 amps is not a particularly large load, but if it were me, I'd invest in at least a 50 foot good quality 12 gauge extension cord. You never know when you'll need it, and it will help on your current project, even if you don't run 12 gauge all the way. I buy mine from the local hardware store, since I like to give them the business when I can. If you are an "advantage member" you can get a good quality one at Northern Tool for less than $50 with free shipping. You can get a slightly less durable one from Harbor Freight for $37 plus shipping.

 

[Sawyer Rob]

My house is #12 and my shop is #12 and #10...

I also have a separate 200 amp service to my shop and it's really all I need.

SR

 

[hosspuller]

Figure it as 150 feet unless you're going to cut one of your cords. IF (A big if) you start with 120 volts, the voltage drop at 7.5 amps will be 5.68. The drill will get 114 volts

Follow John_Mc's advice. Let the drill cool while you're using it.

Here's the calculator

Voltage Drop Calculator