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#182461 - 11/27/08 01:50 PM Another Motor Question *****
invictive Offline
Member

Registered: 11/27/08
Posts: 10
Loc: Victoria, BC
Hi guys,

I've been a long time lurker on the forums, but finally decided to signup today.

I am wiring my own small woodworking shop at the moment and just want to confirm that I am interpreting the code correctly.
I have a 240Volt 7.5HP planer that I am hooking up, its FLA is 32 Amps. It has a Mag switch and thermal protection (not sure on overload).

According to Table D16 (I am using the PS Knight Book 2 as I just moved to BC and don't have the code books yet) this motor would require cable rated at 40 amps (#8 NMD90) and a circuit breaker rated at 80 amps.

No disconnect is required as the machine is in clear sight of the panel which is 25 feet away.
The machine is portable and will be moved around, so it will be hooked up with a short section of SJOW and a twist-lock w/ strain relievers.

I hope this is correct as I have already bought the materials, but I thought I should confirm before doing the install.


Thank you in advance for all your input,

-Kai Thompson

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#182514 - 11/29/08 12:12 PM Re: Another Motor Question [Re: invictive]
Sparky77 Offline
Member

Registered: 11/15/08
Posts: 13
Loc: Alberta
at quick glance every thing seems ok except the 80 amp breaker. #8 nmd90 is only good for 45 or 50 amps meaning your breaker must not be higher rated than the conductor. again that is just a quick glance and all off the top of my head.

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#182533 - 11/29/08 11:05 PM Re: Another Motor Question [Re: Sparky77]
invictive Offline
Member

Registered: 11/27/08
Posts: 10
Loc: Victoria, BC
I said and 80 Amp breaker because Table D16 says that is the "Maximum Allowable Setting for Circuit Breakers of the Time-Limit Type for Motor Circuits"

I was under the assumption that this was to prevent the circuit tripping on motor startup (since this is a single phase motor).

Like I said though, I don't have my code book yet, so I am kind of in the dark.

Also, I cannot find a Twist-Lock that is capable of handing this amperage, therefor I am going to use a "California Style" connector (CS82-65C) rated at 50 Amps.

Thanks again,

-Kai

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#182540 - 11/30/08 11:54 PM Re: Another Motor Question [Re: invictive]
invictive Offline
Member

Registered: 11/27/08
Posts: 10
Loc: Victoria, BC
Ahhh, I did a little more digging and according to Rule 28-602 1b States that a it must have a current rating not less than 115% of the Full Load Current rating of the motor.

So Yes, a 40 Amp breaker will work here, I dont know what Table D16 was on about, its just confusing.

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#182553 - 12/01/08 05:40 PM Re: Another Motor Question [Re: invictive]
mikesh Offline
Member

Registered: 06/07/06
Posts: 614
Loc: Victoria, BC, Canada
Invictive

you have it right the first time. 40 amp wire is OK on an 80 amp breaker because it is a motor. But an 80 amp breaker is the Maximum size for a breaker and a 50 or 60 would be better as long as you don't trip on startup. A 40 might even be adequate. Cord connected with an attachment plug is a disconnecting means so even 50 feet and around a corner works too. There are lots of 50 amp plugs and receptacles available to chose from and an 80 amp pin and sleeve receptacle is a bit rich. Have a look at Meltrac Decontactor products for really high quality plugs and receptacles. They act as disconnects and plugs for true no load disconnection. IE they turn off the power before the plug can be removed. Unplugging a bigger motor under load can create a bad situation. For 3 phase 250 volt a regular twist lock L15-50R. covers it and for a single phase 250 volt L6-50r. No regular plug & receptacle should be opened under load. The rating for your plug comes from the 32 amps and 7.5 HP not the breaker rating. Make sure the type S cable you buy matches the motor temperature rating. 75 degree is only good for ventilated motors of class A and B insulation. 90 degree covers most motors except non ventilated class f and h.

Welcome to Victoria and be careful the City of Victoria has its own inspectors and permit system. All of the other 14 municipalities use the Safety Authority.

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#182554 - 12/01/08 08:39 PM Re: Another Motor Question [Re: mikesh]
twh Offline
Member

Registered: 03/11/04
Posts: 892
Loc: Regina, Sask.
That's a decent sized planer. It makes me wonder if it's a Class III installation.

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#182556 - 12/01/08 09:41 PM Re: Another Motor Question [Re: twh]
invictive Offline
Member

Registered: 11/27/08
Posts: 10
Loc: Victoria, BC
Thanks for the responses everyone, I ended up getting a 40 Amp breaker to start, and if need be I will upgrade it.

mikesh: I tried finding the L6-50R in my Leviton catalogue, but couldn't find it anywhere. Devin at Westburne couldn't find it in their Hubbell Catologue either. I ended up getting at CS8265C and CS8264C instead. They weren't cheap, $150 each.

I wish I had seen those Meltric decontactor plugs before I went shopping, but I'm sure they are pretty pricey. I ended up spending $2000 on Plugs, Connectors, Cabtire and Support Grips to wire up 5 machines. All of the drops will be from the ceiling with full support from grips mounted on buss safety springs. I ended up getting all Hubbell products because that's what Westburne carries, altough I would have preferred Leviton. I got SOOW cable rated at 90 degrees because the motors are all TEFC.

This is a personal installation in a new Woodworking shop I am building for my Father and I. The planer is a 24" production planer/jointer. It weighs over a ton. It has a 3 Phase 600 Volt motor on it, but I am currently rewiring it and installing a 240 Volt Single phase 7.5 HP motor in it. I just moved here from Toronto and unfortunately we can't get 3 Phase where we are located in Saanichton.

I am not an electrician, I was an electrical apprentice for 2 years before deciding I loved woodworking more.

Thanks again,

-Kai

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#182560 - 12/02/08 11:52 AM Re: Another Motor Question [Re: invictive]
mikesh Offline
Member

Registered: 06/07/06
Posts: 614
Loc: Victoria, BC, Canada
http://www.powerfig.com/nema-locking-chart.aspx here is a NEMA configuration chart.
I gotta love Canadian Wholesale. The prefer to carry US products. California standard? Is that like UL California? I doubt many inspectors check the approved configuration is being used. For the most part we only see 15 , 20 , 30 and 50 amp receptacles in houses.

Second a cautionary note. From your posts here you are an apprentice, not an electrician or a contractor. If you are not working under a Contractors permit and supervision you are working illegally. You may not get caught especially if this is one off. But I can tell you I see more and more insurance companies suing to recover cost from persons doing illegal work and possibly even refuse to cover your Dad if there is an accident as a result of an error on your part or simply because a permit was not issued.
I hope you complete your apprenticeship as it sounds like you have a brain and there can never be enough smart tradespeople but don't let your desire to help your dad result in a bad situation for you. You could derail your own career.

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#182576 - 12/02/08 08:18 PM Re: Another Motor Question [Re: mikesh]
dougwells Offline

Member

Registered: 05/03/03
Posts: 1226
Loc: kamloops BC Canada
Quote:
I am not an electrician, I was an electrical apprentice for 2 years before deciding I loved woodworking more.


And on that note this topic is locked.

Thanks Mike for Educating the OP about the rules.

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