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AWG for 2hp, with WJ200-0015SF

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COMachinist

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#1
Hi Everyone
I am installing my VFD with the 2hp 3ph motor sent by Matt at QMT for my PM -932 mill. The tech manual for the Hitachi recommends 10awg wire shielded cable. There does not appear to be room in the motor box for that large of a 4 conductor shielded cable it is tight just getting 12awg 4 conductor shielded in the motor box hole and make the 90 turn to the motor power lugs. No way is the 10 ga doing that. I'm only making about 6 ft Ron from the VFD to the motor. Will 12 wag shielded work for the motor to VFD work? Plus it is only like 10 ft from the main power panel to the VFD enclosure I can run 10awg to that but why use 10 wag to the VFD enclosure when yo only can get 12awg to the motor?
Help is greatly appreciated.
CH
 

81husky

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I ran 10 gage THHN stranded wire for my 935TS and 1340GT, but it is not shielded, and I saw nothing in the manual about shielding being required. The low voltage control wire should be shielded. 10 gage seems like overkill, but I had a bunch on hand, so I used it. Mark will probably chime in and tell you that 12 ga is fine.
 

mksj

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VFD to Motor wire you can use 14AWG for both the 2 and 3Hp VFDs, the manual is specifying the input wire gauge. Input single phase wiring to the VFD I use 12 AWG for the 2 Hp WJ-200-015SF and 10AWG for for 3 Hp WJ200-015SF. I am a bit conservative so on my builds I use the following for the VFD to motor wires 14AWG for 2Hp, 12 AWG for 3Hp and 10AWG for 5Hp, but per online wiring guides 2 and 3 Hp can use 14AWG, 5Hp 12 AWG. Short runs of motor cables do not need to be shielded, but I use it in all my builds with cables more than a few feet and ground the shield at both ends. It is important to cover the shield wire pigtail so it does not short against a live terminal. VFD motor cable needs to have a minimum 600V rating.
 

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Blackjackjacques

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The answer depends on the voltage.

If you are running 240 V, then: (746 W x 2)/.8 = 1865 VARs
Then: 1846 VARs/(1.732 x 240) = 4.4 Amperes. Then 4.4 x 1.15 = 6.66 A.

If you are running 440, then 1865 VARS/(1.732 x 440) x 1.15 = 2.8 A.

So technically you could probably run lamp cord in both cases; however, I'd go 14 gauge. The shield requirement can be addressed with a BX or MC type cable - you should be able to find such a 6 ft whip cable.
 

higgite

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FWIW, the National Electrical Code requires minimum 14 AWG copper for 2 HP 3-phase induction motors rated 575V and below. I would go with 14 AWG copper with the proper rated insulation for max VFD output voltage.

The reason for larger wire to feed the VFD is due to its efficiency. A VFD will draw more than power than it puts out. I would go with mfrs. recommendation for feeder size to the VFD.

Tom
 

COMachinist

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FWIW, the National Electrical Code requires minimum 14 AWG copper for 2 HP 3-phase induction motors rated 575V and below. I would go with 14 AWG copper with the proper rated insulation for max VFD output voltage.

The reason for larger wire to feed the VFD is due to its efficiency. A VFD will draw more than power than it puts out. I would go with mfrs. recommendation for feeder size to the VFD.

Tom
Thanks for your input, all of you. Higgite when you say copper do you mean soild or stranded? All my sheilded cable id stranded copper. And I don,t have any 14awg 4 conductor sheilded.
CH
 

higgite

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Thanks for your input, all of you. Higgite when you say copper do you mean soild or stranded? All my sheilded cable id stranded copper. And I don,t have any 14awg 4 conductor sheilded.
CH
Either one is good. If you use stranded, be sure you get all strands clamped tightly in the connector.

Tom
 

COMachinist

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The answer depends on the voltage.

If you are running 240 V, then: (746 W x 2)/.8 = 1865 VARs
Then: 1846 VARs/(1.732 x 240) = 4.4 Amperes. Then 4.4 x 1.15 = 6.66 A.

If you are running 440, then 1865 VARS/(1.732 x 440) x 1.15 = 2.8 A.

So technically you could probably run lamp cord in both cases; however, I'd go 14 gauge. The shield requirement can be addressed with a BX or MC type cable - you should be able to find such a 6 ft whip cable.
There is no 440 available out here in the boonies. I on rual power out here and I would have to pay for running any other power the 3 miles from the power company. I have 250 each leg reads 124-125vac to earth ground at 200 amp. 3ph would cost about 10,000 if I had a ag permit, for a deep well pump, but I don’t have that either. 240/250vac is what I have.
Thanks
CH
VFD to Motor wire you can use 14AWG for both the 2 and 3Hp VFDs, the manual is specifying the input wire gauge. Input single phase wiring to the VFD I use 12 AWG for the 2 Hp WJ-200-015SF and 10AWG for for 3 Hp WJ200-015SF. I am a bit conservative so on my builds I use the following for the VFD to motor wires 14AWG for 2Hp, 12 AWG for 3Hp and 10AWG for 5Hp, but per online wiring guides 2 and 3 Hp can use 14AWG, 5Hp 12 AWG. Short runs of motor cables do not need to be shielded, but I use it in all my builds with cables more than a few feet and ground the shield at both ends. It is important to cover the shield wire pigtail so it does not short against a live terminal. VFD motor cable needs to have a minimum 600V rating.
Mark I have 12awg 4 cond. sheilded so that looks good to use for both in/output power? I can run that through som 3/4” hard conduit but hate to have my mill hard fixed to the wall box..
thanks.
CH
 

COMachinist

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Either one is good. If you use stranded, be sure you get all strands clamped tightly in the connector.

Tom
Hi Tom
Figured to tin the leads that will go in the crimped connectors. so nothing is hanging out.
CH
 

mksj

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I recommended using stranded wire, solid wire can fatigue with vibration/movement. On the input power to the VFD I would just use something like SOOW 12AWG 3 conductor, if you need a neutral to pull off 120V for sockets you would want 4 conductor. You can use the shielded, but no reason to do so on the input power to the VFD. Alternatively you could use some 3/4 flexible plastic conduit (or liquid tight with a metal spiral) and pull individual stranded wires through if you hardwired to a box (I do this on my compressor), if plug then just use flexible power cable and add a plug. You do not need to run it through hard conduit. On the motor cable what you are using is fine, but you will need 3/4" strain reliefs st either end due to the size of the cable. You are only running a 2Hp VFD, so you do not need to go overboard with the wire. I run mine off a 20A breaker with not problems, I use 12AWG flexible power cord to my 2Hp VFD because of the distance. There are some requirements for VFD installations that require wiring/breaker to be at least 125% of the VFD rating (not load), so it is not just a Hp calculation. You can do the calculations for all this, but also want to follow the VFD manufacture's directions.

Compressor.jpg
 

higgite

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Mark I have 12awg 4 cond. sheilded so that looks good to use for both in/output power? I can run that through som 3/4” hard conduit but hate to have my mill hard fixed to the wall box..
thanks.
CH
Please don't take this question as an insult, but I don't know what you know or don't know about electrical wiring. Your multi-conductor cable is shielded, that is, it has a metallic shield under the insulation? Or is it flexible armored cable? There is a difference.

As for the connection between wall box and mill, I wholeheartedly agree it should be flexible so as not to transmit vibration.

Tom
 

COMachinist

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#12
Please don't take this question as an insult, but I don't know what you know or don't know about electrical wiring. Your multi-conductor cable is shielded, that is, it has a metallic shield under the insulation? Or is it flexible armored cable? There is a difference.

As for the connection between wall box and mill, I wholeheartedly agree it should be flexible so as not to transmit vibration.

Tom
LOL yea I’m not up to speed on electrical stuff, I am gad ME but i was in school several years ago. I only took a basic coarse in eletronics and I damn near failed that. I know basic electral knowledge but I don’t qualifie as a journeyman. I do most of what i have done with about 50% safty factor:cool:
CH
 

COMachinist

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#13
The cable I have is from automationdirect it is the vfd 12/4 sheilded with drain wire under the sheild.between the foil raped around wires an insulation strands. It is rated -40 to 90C 600 volts oil Resistant I/II , and it is grey. I bought it a while ago for my cnc mill motor cable and this was left over. It came in the cnc kit they used to sell. I never used it because I installed a dc 1.5 hp motor with encoder on ithe mill.
CH
 
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