Can I use an extension cord??

Can I use an extension cord?? · 02-19-2008, 11:18 PM

I have a very small one car garage for my shop and unfortunately, I have one plug in the garage. Due to this, I have been using an extension chord when running my heavy tools (table saw, planer, etc) that can't be easily or conveniently relocated over to the plug. The chord appears to be a pretty heavy cord and has a ground socket on it. I was talking to a co-worker of mine and he said that using an extension cord on some of my heavier tools could actually ruin them in the long run. Is this true? He also stated that I might be able to run them off a extension cord but it should be a special cord designed for such tools. I really have no idea of what I should look for in a cord and wouldn't even know where to begin. Can anyone confirm what he's saying and have any advice for the type of cord I'd need?

NCPete · 02-19-2008, 11:23 PM

I built an extension 'cord' using 12 gauge romex to handle just such situation in my shop. it is rare the commercially available consumer grade cords will support larger tools, look for one that will handle 20 amp load, but probably not any longer than 25 feet.

scsmith42 · 02-19-2008, 11:26 PM

Scott, typically to determine the sufficiency of an extension cord it needs to be sized appropriately. Larger diameter wire is better; too small a wire and you can suffer voltage drops and ruined tools.

If your cord uses 12 or 10 guage wire, odds are that it will be ok.

To find out for sure, check to see what the amperage rating are on your various tools, and determine which tool draws the greatest amps. If it's 15 amps or less, you should be ok with a 12 guage extension cord.

The other dimension that comes into play is the total length of the circuit, including from the load center to your outlet, the length of the cord, and the length of the cord attached to your equipment. The factor at play here is the resistance in the circuit; basically all wire has resistance and the longer the wire, the greater the resistance. Most electric codes call for a maximum of 2% voltage drop over the length of the circuit. Too long a wire, or too small a wire, and you can exceed this spec.

Usually you want to use the shortest length extension cord that will work for you, and the largest diameter wire.

If you'll check the nameplates on the electric motors in question, and check your extension cord to see if it has any numbers printed or stamped in it, post the info and either myself or one of the others can get your the voltage drop info.

Scott

Joe Scharle · 02-19-2008, 11:32 PM

Without going into a lot of technical stuff; if the cord feels very warm in your fist while or just after using your equipment, then you best stop using it.

Bas · 02-19-2008, 11:34 PM

No, you cannot use an extension cord. Instead, you need to completely remodel the garage (tripling it in size), with 110V and 220V outlets every 4 feet. Install dust collection and compressed air while you're at it. And buy some new tools to fill that space.

(Show only the above section in to the LOYL - do not show the section below!

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Yes, you can use an extension cord. You just have to make sure it's beefy enough to handle the load generated by the tools. I suggest you get a cord that's 12AWG (=12 gauge = thickness of the copper conductors in the cord. The lower the number, the thicker the cable). You can buy either a pre-made cord, or make one yourself. The former may be difficult, most home centers do not usually sell something that heavy. The heaviest is usually only 14AWG. You should be able to find one on-line or at a specialty store.

Before going into the DIY option (which really is not very difficult), let's make sure you'd be comfortable doing that. If you've ever wired a lamp, plug, or installed a switch, you should be OK. You can buy the materials to make an extension cord at Home Depot or Lowe's.

You mentioned this is a small one-car garage, so I assume you only need about 10ft of cord, right? If you need a really long extension cord, then you may consider going to 10AWG.

As far as ruining your tools - your friend has a point. If you overload your extension cord, all sorts of bad things can happen. Just like you can blow up your speakers if you hook them to a powerful amplifier, using an undersized cable can damage your tools.

Makinsawdust · 02-20-2008, 12:00 AM

Originally Posted by Bas

You can buy either a pre-made cord, or make one yourself. The former may be difficult, most home centers do not usually sell something that heavy. The heaviest is usually only 14AWG. You should be able to find one on-line or at a specialty store.

Bas,
All the borg's have 12awg cords. Take a look. They are usually yellow in color.
Rob

RobD · 02-20-2008, 10:24 AM

Wow, thanks for asking this question. I am in the same boat (garage with 1 outlet) and it sounds like I need to upgrade my extension cord.

woodnick · 02-20-2008, 10:56 AM

One very important thing that I don't think was talked about is the receptacles BUY the best ones you can find there's just as much lost in cheap receptales as there is in the cord

DaveD · 02-20-2008, 11:54 AM

The borgs have extension cords made with both #12 and sometimes even #10 wire. Unless you are talking somewhere in the 75-100' range from the panel to the power tool I wouldn't worry about voltage drop.

The NEC (National electrical code) does have a statement (in article 430) about branch circuit conductors, supplying a single motor, having an ampacity not less than 125% of the motor full-load current rating). So I would use the same logic for the extension cord.

I'd also recommend you cut the female end off the extension cord and put on a metal quad box that can hold two duplex receptacles. Buy GOOD heavy duty duplex recptacles, not the 89 cent ones. It gets real old in a hurry plugging tools on/off a single plug at the end of a cord.

sediener · 02-20-2008, 03:40 PM

I ordered an RV extension cord for my more power hungry tools. 10gauge 30 amp 25ft 30$

http://www.rvupgradestore.com/browse...--25'.HTML

- Steve

cpowell · 02-20-2008, 09:24 PM

Originally Posted by Boilermaker

I have a very small one car garage for my shop and unfortunately, I have one plug in the garage. Due to this, I have been using an extension chord when running my heavy tools (table saw, planer, etc) that can't be easily or conveniently relocated over to the plug. The chord appears to be a pretty heavy cord and has a ground socket on it. I was talking to a co-worker of mine and he said that using an extension cord on some of my heavier tools could actually ruin them in the long run. Is this true? He also stated that I might be able to run them off a extension cord but it should be a special cord designed for such tools. I really have no idea of what I should look for in a cord and wouldn't even know where to begin. Can anyone confirm what he's saying and have any advice for the type of cord I'd need?

I ran a few calcs based on ohms/ft values I found online (my code book is at the office). A 30 amp load on 14AWG, 50 ft long extension cord would drop around 4 volts. At 15 amps running load you would drop around 2 volts. So, if you have a 14 gauge cord up to 50 feet you should be fine running a typical 15 amp machine.

12AWG is overkill unless you are talking about a LONG distance. I rigged a 12 gauge cord for a generator connection from a neighbor's house, well over 100 feet. Now that was a long run.

Most of the problems I've seen with ext cord use is actually at the PLUG/outlet connection (as woodnick mentioned). Loose/sloppy fit generates heat.

Usual disclaimers apply - don't use the cord if it's frayed, etc.

Chuck