Breaker and wire size help - Page 4 - Electrician Talk - Professional Electrical Contractors Forum
CLICK HERE AND JOIN OUR COMMUNITY TODAY, IT'S FREE!
Go Back   Electrician Talk - Professional Electrical Contractors Forum > Electrical Trade Topics > Commercial Electrical Forum


Like Tree33Likes
Reply
 
Thread Tools Display Modes
Old 12-09-2018, 02:26 PM   #61
Band Member
 
emtnut's Avatar
 
Join Date: Mar 2015
Location: Eastern Ontario
Posts: 5,635
Rewards Points: 638
Default

Quote:
Originally Posted by Cow View Post
I disagree, that's not what the article I posted says.
Interesting. Under CEC, motor data trumps the tables.

For your NEC, would exception #3 not apply here (under 430.6) ?
__________________
_____________________________________
Your Mother was a hamster, and your father smells of Elderberries. ... Now go away, or I shall taunt you a second time
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
emtnut is offline   Reply With Quote
Join Contractor Talk

Join the #1 Electrician Forum Today - It's Totally Free!

ElectricianTalk.com - Are you a Professional Electrical Contractor? If so we invite you to join our community and see what it has to offer. Our site is specifically designed for you and it's the leading place for electricians to meet online. No homeowners asking DIY questions. Just fellow tradesmen who enjoy talking about their business, their trade, and anything else that comes up. No matter what your specialty is you'll find that ElectricianTalk.com is a great community to join. Best of all it's totally free!

Join ElectricianTalk.com - Click Here JOIN FOR FREE


Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. ElectricianTalk.com DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!

Sponsored Links
Advertisement
 
Old 12-09-2018, 03:14 PM   #62
Senior Member
 
WronGun's Avatar
 
Join Date: Oct 2013
Location: USA
Posts: 1,945
Rewards Points: 644
Default Breaker and wire size help

Today I went to the building where I got to enter the neighbors adjacent unit who has the same identical compressor unit. (Which is the reason he bought his)

Installed with 10awg thhn on a 40A breaker, itís been running now for a year. Not sure if the installer was the same.

This now becomes hard for me to explain if I need to run all new pipe , wires , etc.

Pipework in these units are about 16í-18í high , 80í from panel, so its a bit of work.

Sent from my iPhone using Tapatalk
847Videos likes this.

Last edited by WronGun; 12-09-2018 at 03:20 PM.
WronGun is offline   Reply With Quote
Old 12-09-2018, 03:21 PM   #63
Senior Member
 
847Videos's Avatar
 
Join Date: Dec 2014
Location: Illinois
Posts: 115
Rewards Points: 96
Default

Iíd design and install it based on the national electrical code, the Chicago code says you take ownership of what you install, so if something happens, and you find yourself in court having to justify what you did, the ďNieghborĒ hired an untrained handy man so I copied his design wonít fly




Sent from my iPhone using Tapatalk
847Videos is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 12-09-2018, 03:27 PM   #64
Senior Member
 
Join Date: Dec 2010
Location: So.Cal.
Posts: 3,338
Rewards Points: 6,625
Default

Quote:
Originally Posted by WronGun View Post
After reading the article and other posts on this subject Iíve found a dozen different answers....


Sent from my iPhone using Tapatalk
That seems to be the standard in this trade. Get 10 electricians together, and get 10 different ways to do the exact same thing.
micromind and jelhill like this.
__________________
-------------------------------
~ She thinks I'm crazy, but I'm just growing old~
joebanana is offline   Reply With Quote
Old 12-09-2018, 03:32 PM   #65
Senior Member
 
847Videos's Avatar
 
Join Date: Dec 2014
Location: Illinois
Posts: 115
Rewards Points: 96
Default

Quote:
Originally Posted by joebanana View Post
That seems to be the standard in this trade. Get 10 electricians together, and get 10 different ways to do the exact same thing.



Look at the thread, @Cow laid it out correctly



847Videos is offline   Reply With Quote
Old 12-09-2018, 03:42 PM   #66
Senior Member
 
Join Date: Dec 2010
Location: So.Cal.
Posts: 3,338
Rewards Points: 6,625
Default

Quote:
Originally Posted by WronGun View Post
Today I went to the building where I got to enter the neighbors adjacent unit who has the same identical compressor unit. (Which is the reason he bought his)

Installed with 10awg thhn on a 40A breaker, itís been running now for a year. Not sure if the installer was the same.

This now becomes hard for me to explain if I need to run all new pipe , wires , etc.

Pipework in these units are about 16í-18í high , 80í from panel, so its a bit of work.

Sent from my iPhone using Tapatalk
So just for my own curiosity, did you put an amprobe on the circuit? How about a voltage reading at the load? My point being, you've got approx. 112' from the panel, what's the V/D?
__________________
-------------------------------
~ She thinks I'm crazy, but I'm just growing old~
joebanana is offline   Reply With Quote
Old 12-10-2018, 12:04 AM   #67
Bilge Rat
 
Join Date: Aug 2007
Location: Fernley, Nevada (near Reno)
Posts: 6,407
Rewards Points: 2,426
Default

Quote:
Originally Posted by WronGun View Post
Today I went to the building where I got to enter the neighbors adjacent unit who has the same identical compressor unit. (Which is the reason he bought his)

Installed with 10awg thhn on a 40A breaker, itís been running now for a year. Not sure if the installer was the same.

This now becomes hard for me to explain if I need to run all new pipe , wires , etc.

Pipework in these units are about 16í-18í high , 80í from panel, so its a bit of work.

Sent from my iPhone using Tapatalk
Just because it works doesn't mean it's code compliant.

On the other hand, because this installation works, it casts serious doubt on the validity of the code.......
splatz and Kevin_Essiambre like this.
micromind is online now   Reply With Quote
Old 12-10-2018, 05:31 AM   #68
Hackenschmidt
 
splatz's Avatar
 
Join Date: May 2015
Location: Parts Unknown
Posts: 7,987
Rewards Points: 3,376
Default

Quote:
Originally Posted by micromind View Post
Just because it works doesn't mean it's code compliant.
Very true. I also don't assume because it worked for someone, sometime, it will work for me, today. Motors are not perfect, it might work for that one but not another.

If you do it to the letter / by the numbers, then if there's an issue it's not on you.
micromind likes this.
__________________
Everything Should Be Made as Simple as Possible, But Not Simpler
splatz is offline   Reply With Quote
Old 12-10-2018, 05:54 AM   #69
Senior Member
 
WronGun's Avatar
 
Join Date: Oct 2013
Location: USA
Posts: 1,945
Rewards Points: 644
Default

I agree, and thatís what Iím going to price it out for , but technically what can happen?

At the panel itís Protected by a 30a breaker and right before the starter itís Protected by a 30a fused disco.

The worst that can happen? it trips...2 points of protection would need to fail..... just sayin....


Sent from my iPhone using Tapatalk
WronGun is offline   Reply With Quote
Old 12-10-2018, 06:11 AM   #70
Elderly Member
 
jelhill's Avatar
 
Join Date: Nov 2018
Location: The Volunteer State
Posts: 549
Rewards Points: 1,090
Default

Quote:
Originally Posted by WronGun View Post
We tested it today and it only trips as it get closer to full fill


Sent from my iPhone using Tapatalk
Iím curious... did you have an amp meter on the #10 feeder (line side) when you were doing you start-up tests? What actual readings were you getting? Use the stop button on the meter and record 2 or 3 tries. In addition to you being under-sized with the #10 and 30/2 breaker.... you may have a weak breaker.
__________________
....
jelhill is offline   Reply With Quote
Old 12-10-2018, 06:13 AM   #71
Senior Member
 
Join Date: May 2018
Location: florida
Posts: 1,332
Rewards Points: 880
Default

just adjust the pressure switch down by 20 psi and call it good to go.

Less psi = less load = less amps
gpop is offline   Reply With Quote
Old 12-10-2018, 06:29 AM   #72
Elderly Member
 
jelhill's Avatar
 
Join Date: Nov 2018
Location: The Volunteer State
Posts: 549
Rewards Points: 1,090
Default

Quote:
Originally Posted by gpop View Post
just adjust the pressure switch down by 20 psi and call it good to go.

Less psi = less load = less amps
Good point... I wonder if the customer even has a specific PSI requirement.
__________________
....
jelhill is offline   Reply With Quote
Old 12-10-2018, 06:42 AM   #73
Senior Member
 
WronGun's Avatar
 
Join Date: Oct 2013
Location: USA
Posts: 1,945
Rewards Points: 644
Default

Quote:
Originally Posted by jelhill View Post
Good point... I wonder if the customer even has a specific PSI requirement.


Itís a very small excavation company , they are just using this to maintain the fleet


Sent from my iPhone using Tapatalk
WronGun is offline   Reply With Quote
Old 12-10-2018, 09:51 AM   #74
Elderly Member
 
jelhill's Avatar
 
Join Date: Nov 2018
Location: The Volunteer State
Posts: 549
Rewards Points: 1,090
Default

Quote:
Originally Posted by WronGun View Post
Itís a very small excavation company , they are just using this to maintain the fleet


Sent from my iPhone using Tapatalk
Then @gpop is right... try adjusting the pressure regulator.
__________________
....
jelhill is offline   Reply With Quote
Old 12-10-2018, 10:05 AM   #75
Elderly Member
 
jelhill's Avatar
 
Join Date: Nov 2018
Location: The Volunteer State
Posts: 549
Rewards Points: 1,090
Thumbs up

Quote:
Originally Posted by WronGun View Post
I am a licensed electrician. Didnít know that the electrical license means you know every possible thing in the trade. ...

This is in an industrial setting as I stated 208V

I havenít installed anything yet just checking before i do anything.

I donít have much experience hooking up compressors. The owner who is my client just took the old compressor feeds and popped them into the new compressor which has all the same specs on name plate and now called me in because itís tripping.

Both the old and new compressor have built in motor staters with a terminal for L1, L2, and ground...


Sent from my iPhone using Tapatalk






You asked a very legitimate question, just look at all the (Positive) responses you got.
__________________
....
jelhill is offline   Reply With Quote
Old 12-10-2018, 11:29 AM   #76
Vacated
 
Wiresmith's Avatar
 
Join Date: Feb 2013
Location: United States
Posts: 1,452
Rewards Points: 2,840
Default

i don't have my code book with me but vfds require i think 125% wire ampacity of the vfd rating, and often you use a larger vfd than the motor for several reasons. i think in the code book in motor section it is under something like motor controlling equipment or something like that.

also the new motor may be tripping because its a different efficiency motor than the last. sounds like it had wrong wiring before though, just offering of why same spec motor and now it trips. ratings only mean so much, take current readings on the similar compressor that's running. it says right on it 31 amps.
__________________
Think like a man of action, act like a man of thought. ~Henri Louis Bergson

Last edited by Wiresmith; 12-10-2018 at 11:34 AM.
Wiresmith is offline   Reply With Quote
Old 12-10-2018, 12:00 PM   #77
Senior Member
 
sbrn33's Avatar
 
Join Date: Mar 2007
Location: middle america
Posts: 11,399
Rewards Points: 3,198
Default

This is a #8 on a 60 amp breaker all day long. I know you like to run with it on this site but just do it right and be done.
I know you know what you are doing, but in this thread you definitely do not sound like it. You sound like a mechanic that just keeps replacing parts until it works. Hard to make money that way.
sbrn33 is offline   Reply With Quote
Old 12-10-2018, 05:28 PM   #78
Modťrateur
 
frenchelectrican's Avatar
 
Join Date: Mar 2007
Location: Philippines
Posts: 8,594
Rewards Points: 16,698
Default

Quote:
Originally Posted by sbrn33 View Post
This is a #8 on a 60 amp breaker all day long. I know you like to run with it on this site but just do it right and be done.
I know you know what you are doing, but in this thread you definitely do not sound like it. You sound like a mechanic that just keeps replacing parts until it works. Hard to make money that way.
I agree with Sbrn and he did bring up couple very good points reguarding of the set up.
If I were you .,, I would rip the #10 chit out and run in correct size conductor and correct breaker size and be done with it and not have to worry about callback or other issue.

#10 on 208 with 30ish amp and ya are pushing the limit on voltage drop those compressor motor dont like too low a voltage so be aware of it.
__________________
Bleu est beau.
frenchelectrican is offline   Reply With Quote
Old 12-10-2018, 06:25 PM   #79
Senior Member
 
460 Delta's Avatar
 
Join Date: May 2018
Location: Southern Ohio
Posts: 597
Rewards Points: 562
Default

If they have 208 VAC, I wonder why they didn't order a 3 phase motor? Is this by chance the same place that had the issue with smoking the Siemens starters?
__________________
Perfection is the enemy of good enough
460 Delta is offline   Reply With Quote
Old 12-10-2018, 06:36 PM   #80
Senior Member
 
WronGun's Avatar
 
Join Date: Oct 2013
Location: USA
Posts: 1,945
Rewards Points: 644
Default Breaker and wire size help

Quote:
Originally Posted by 460 Delta View Post
If they have 208 VAC, I wonder why they didn't order a 3 phase motor? Is this by chance the same place that had the issue with smoking the Siemens starters?


If they had reached out to me first , I wouldíve advised them to go with 3-phase...

Same industrial building , different tenant.

We replaced the starter on that job and also a new 3-phase compressor, all good.

I dont know why people insist on keeping these pieces of equipment that date back to the 40ís

weíve been replacing some of the tenants really old compressors, all have been 3-phase.

All the 3-phase units were installed correctly. These couple of single phase units are cutting it too close.



Sent from my iPhone using Tapatalk

Last edited by WronGun; 12-10-2018 at 07:57 PM.
WronGun is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Is this Electrician correct on wire sizing? grover1134 General Electrical Discussion 10 11-05-2018 07:15 PM
Heating Loads and Wire Size darren79 Canadian Electrical Forum 2 01-20-2017 07:33 PM
60 amp double pull breaker on 12, 14 gauge wire. Gamble Residential Electrical Forum 7 09-24-2016 05:35 PM
Is this overkill? MTW NEC Code Forum 81 03-20-2016 09:26 PM
Help with this a/c breaker sizing TechieBecky Canadian Electrical Forum 73 02-27-2016 06:26 PM


All times are GMT -4. The time now is 01:19 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Our Pro Sites Network
ContractorTalk.com | DrywallTalk.com | HVACSite.com | PaintTalk.com | PlumbingZone.com | RoofingTalk.com