220 volt extension cord

[Keye]

I want to move my table saw location. The cord will end up being about 10 feet short. Will an extension cord create any problem? I know a new cord would be best but I am thinking the cord might be less expensive, quicker and easier.

3hp, single phase, 240v 30 amp breaker delta unisaw

 

[bowman]

You can use this to make a replacement cable, you will just need a male end to attach. Good for 25 amps.

https://www.lowes.com/pd/25-ft-12-A...SrKKg1aa8hqtEF0s0-RoCbyUQAvD_BwE&gclsrc=aw.ds

 

[Melinapex]

That's what I did - bought an extension cord- about ten years ago..... found it at one of the borgs... no problems....

 

[RickR]

I run my 3hp/220v unisaw on a 10ft extension in the winter when I move my saw to allow parking for a car. I have not had any problems. I think my cord is #12. You may need to hunt some to find the appropriate male and female ends.

 

[waitup]

You can buy 10 gauge cords as well. I have a 100' one so I don't have to worry about burning up 120v tools.

 

[Oka]

You can get SO cord (thick rubber cord) or any other good quality 10 or 12 ga cord.

For a 3hp 220 system 12 ga @ 25 ft will suffice. If you decide you need something over 50 ft then 10 ga should be used.

Depending on the efficiency of the motor those 3 hp/220 motor typically run 10-12 amp draw. 12 ga is a 20 amp rated. If possible buy cord with THHN insulation (90c). This is added protection.

 

[Keye]

You can use this to make a replacement cable, you will just need a male end to attach. Good for 25 amps.

https://www.lowes.com/pd/25-ft-12-A...SrKKg1aa8hqtEF0s0-RoCbyUQAvD_BwE&gclsrc=aw.ds

Looks like it is going to be an extension cord. I can not remove the cover for the electrical connections. My Unisaw is circa 1994 and the screw heads are a single slot. If I am going to drill them out I want it to be because I do not have a choice.

Lowes is 2 hours round trip and HD is only 40 minutes round trip. Hopefully HD has what I need.

Thanks for the help and comments.

 

[tvrgeek]

I would use 10 gauge minimum. 12 gauge stranded is not 30A rated. You may do better with something like

https://www.amazon.com/Champion-250-Volt-Generator-Power-Transfer/dp/B076HQ2THC/ref=asc_df_B076HQ2THC?tag=bngsmtphsnus-20&linkCode=df0&hvadid=80470624769013&hvnetw=s&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=&hvtargid=pla-4584070153429494&psc=1

I guess I don't understand the problem with "single slot".

Home Despot may have something similar.

 

[Dee2]

from my (limited) experience, electrical cords are cheaper at an electrical supply house but you have to make up the ends. YMMV.

 

[tvrgeek]

Yup, but the ends can be expensive.

 

[Oka]

The Voltage as stated is 240v/single phase 3 hp, that means with an typical motor average of 85% eff would equal a running load of just under 11 amps.

120v/3hp would have a rating of roughly 22 amps running load.

Per the NEC Table 310-16 it allows 30 amps start load on 12 gauge stranded THHN, PFA and other high temperature wire insulating sheathing. Stranded is preferred because of the increased KMil rating (surface area) tends to not heat up as bad as solid. That said, later in 240.4 table refers to limiting max amps on 12 ga to 25 amps. This is typical in the code. One reason is with higher amps = more heat, so you need the wire 90c heat rated (THHN). However, all connections must also be 90c rated and often that information is hard to determine since not all spec data is provided or lookup-able. As such, the code then builds in its own safety factor. This is where in these cases, you need a experienced Elec Engineer to provide accurate and intelligent recommendations. Otherwise, you end up with a rookie calling out a more expensive design.- Bit of a rant
But, to the question 3hp/240/ single phase- a 12 gauge cord 25ft is sufficient with a voltage drop of less than 1.4 v @ 15 amps.

I would use 10 gauge minimum. 12 gauge stranded is not 30A rated. You may do better with something like

https://www.amazon.com/Champion-250-Volt-Generator-Power-Transfer/dp/B076HQ2THC/ref=asc_df_B076HQ2THC?tag=bngsmtphsnus-20&linkCode=df0&hvadid=80470624769013&hvnetw=s&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=&hvtargid=pla-4584070153429494&psc=1

I guess I don't understand the problem with "single slot".

Home Despot may have something similar.

 

[tvrgeek]

Minimum code is to prevent fire, not proper performance. I stand by the suggestion to use 10 gauge cordage. ( plus my years in failure analysis where we dealt with 30 to 400A 208 and 480)

 

[Rwe2156]

Rather than an extension cord, I attached a box and outlet directly on the machine bases for my table saw and planer. I used flex conduit and followed the dust collection hoses. I don’t know if this is ”kosher”, but my machines have been this way for almost 25 years.

 

[Keye]

You can use this to make a replacement cable, you will just need a male end to attach. Good for 25 amps.

https://www.lowes.com/pd/25-ft-12-A...SrKKg1aa8hqtEF0s0-RoCbyUQAvD_BwE&gclsrc=aw.ds

$22 at Lowes
$49 at HD

 

[Keye]

One last comment, the cable on the saw is 14/3.

 

[bowman]

One last comment, the cable on the saw is 14/3.

and that's probably fine for for the factory 6' cable. If it were mine, I would make a longer cable with the 12/3

 

[Hmerkle]

I was trying to stay out of this because the code is one thing, what I would do is another and there are good points all around for wire size for the "extension cord"

But, @Keye stated "3hp, single phase, 240v 30 amp breaker delta unisaw"

If I have a 30 Amp breaker, I want a cable capable of carrying 30 amps for a period of time. (We may have the saw running for quite a while while sawing, adjusting, sawing etc...)

In my home, all 30 AMP circuits have 10 AWG wire, so that is what I would attempt to copy in a "DIY extension cord." If I couldn't get that, I would opt for a 12 AWG cable.

YMMV, JMHO

 

[Charles Lent]

It's the in-rush current that makes the 30 amp rating. The code allows the in-rush to be 150 % of the cable and breaker ratings. That said, if your breaker is 30 amps, I would not use wire smaller than 10 gauge to connect the saw.

A 20 amp breaker with delayed trip to account for the 150% in-rush current during the motor start cycle, and 12 gauge wire is actually sufficient for a 3 hp 240 volt Unisaw. Use 240 volt 20 amp plug and outlet configurations with the power pin or both pins turned 90 degrees from the normal 120 volt plug, and matching receptacle configuration to prevent damaging a 120 volt tool from being plugged into this power source.

There are 12 ga extension cords with the 90 deg power pin available, and they are cheaper than buying the pieces to put on bulk 12 SJO type cable. Think window 240 volt Air Conditioner Extension Cables. 3-10ft lengths are readily available.

Charley

 

[golfdad]

Agrees with Scott. 10ga min. Our company 240 volt machines dont get hooked up with anything higher than 8 gauge.

 

[tvrgeek]

One last comment, the cable on the saw is 14/3.

Just as stupid as the DeWalt planers with 15A plugs and a 17A internal breaker which pull closer to 20A continuous running. Stupid is as stupid does. So much for UL and CSA. DeWalt could have done us a big favor and allowed wiring for 110 or 220. So, job site run on 110, shop use on 220.

It is smart to different between preventing a fire and actually working well.

The plug you use is defined by the spec. Nema R620 or 630 depending. Receptacle must not exceed the branch breaker and cable. I actually prefer the locking, L620 etc.