DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   Electrical (http://www.diychatroom.com/f18/)
-   -   Wire, Conduit and Voltage Drop Questions (http://www.diychatroom.com/f18/wire-conduit-voltage-drop-questions-39287/)

kikdrum 02-27-2009 04:30 PM

Wire, Conduit and Voltage Drop Questions
 
I've been out of the field for quite some time and was asked by my employer to run a feed for new offices in our buildings.
Here's the first question:
The run is 95 feet and it will take a 220v, 60 amp main from the existing panel. I was going to run #6-black, red and white with a #8 ground in 1" EMT.
Am I on the right track?
Here's the second question:
In the other building there is no room for more breakers. Again, tell me if I'm on the right track. I was going to remove 2 20 amp breakers from the existing 200amp panel, install a 100amp breaker and run the feed to a subpanel. At the subpanel I'll install the 2 20amp breakers along with the 60amp breaker needed to feed the new offices.
Thanks in advance for your help.

Mike

jamiedolan 02-27-2009 05:16 PM

Quote:

Originally Posted by kikdrum (Post 237842)
I've been out of the field for quite some time and was asked by my employer to run a feed for new offices in our buildings.
Here's the first question:
The run is 95 feet and it will take a 220v, 60 amp main from the existing panel. I was going to run #6-black, red and white with a #8 ground in 1" EMT.
Am I on the right track?
Here's the second question:
In the other building there is no room for more breakers. Again, tell me if I'm on the right track. I was going to remove 2 20 amp breakers from the existing 200amp panel, install a 100amp breaker and run the feed to a subpanel. At the subpanel I'll install the 2 20amp breakers along with the 60amp breaker needed to feed the new offices.
Thanks in advance for your help.

Mike

3 - 6awg and a 10awg ground easily fit in 3/4 EMT.

Since your employed by someone, it may not be legal for you to do this work without a license.

Yes, that sounds like a typical way to install a sub panel.

Jamie

kikdrum 02-28-2009 08:15 AM

As far as a license is concerned (it was a BIG concern of mine) they are planning on having someone, a licensed friend, to come in and inspect the work. I guess he'll put his name on it. I've done tons of electrical work in the past but been out of the trade for about 12 years now. I know how important it is for things to be right. That's why I posted here.
As for my employer, he likes everything to be legit so I'm sure he'll do whatever it takes to keep it legal.

So, a 100' run with #6 is fine for a 60amp circuit?

Thank you for your help.

chris75 02-28-2009 08:56 AM

Quote:

Originally Posted by kikdrum (Post 238079)
As far as a license is concerned (it was a BIG concern of mine) they are planning on having someone, a licensed friend, to come in and inspect the work..

Then tell your boss to hire an electrician. :no:

Stubbie 02-28-2009 09:55 AM

You need an electrician to do commercial work, just about everywhere.

This is making no sense to me.....

Quote:

Again, tell me if I'm on the right track. I was going to remove 2 20 amp breakers from the existing 200amp panel, install a 100amp breaker and run the feed to a subpanel. At the subpanel I'll install the 2 20amp breakers along with the 60amp breaker needed to feed the new offices.
You also need to check about what voltages your dealing with. you could very well be in a 200 amp 120Y208 panel which is ok but you need to know what your doing.

Scuba_Dave 02-28-2009 10:12 AM

What wire is the 100a breaker feeding?
The #6 wire ?

wirenut1110 02-28-2009 10:29 AM

He's going to remove 2-20 amp breakers from the main panel to make room for a new 100 amp breaker to feed a 100 amp panel. Off that new 100 amp sub panel he's going to feed the 2-20 amp circuits, he removed to make room for the 100 amp breaker, and feed another 60 amp sub panel off of that for the "office".

Yoyizit 02-28-2009 12:01 PM

Quote:

Originally Posted by kikdrum (Post 238079)
So, a 100' run with #6 is fine for a 60amp circuit?

50 milliohms/1000' for #6, times 200'= .010 ohm. (60A)(.01) = 0.6v drop. (100)0.6v/220v = ~0.3%.
Looks OK for voltage drop.

I think your employer wants to save money and does not much care about your safety. You could tell him that you researched this and you need costly arc flash protection gear.

Employers tend to use whoever is standing next to them to do whatever job is required. You really do not have the option to refuse, either.

"If a person signs a document stating that he or she is aware of the hazards of an activity, and that individual is then injured during that activity, the express consent given in advance may excuse another person who caused an injury to that person."

kikdrum 03-01-2009 07:17 AM

Quote:

Originally Posted by Stubbie (Post 238123)
This is making no sense to me.....

Wow! Is it really that confusing??


Quote:

Originally Posted by wirenut1110 (Post 238146)
He's going to remove 2-20 amp breakers from the main panel to make room for a new 100 amp breaker to feed a 100 amp panel. Off that new 100 amp sub panel he's going to feed the 2-20 amp circuits, he removed to make room for the 100 amp breaker, and feed another 60 amp sub panel off of that for the "office".

Thanks, wirenut!

I really like doing this kind of work and have the utmost respect for you guys that have taken it to the furthest level. I left the trade to pursue a different career.
When I did it for a living it was 90% industrial. Most of the conduit we ran was aluminum and galvanized. We ran everything from 1/2" to 4" and wire up to 750 mcm.
My employer has knowledge of my background and politly asked if I would be interested. If you're the kind of person who likes a challenge and get the chance, you would probably jump at the opportunity as well.
I know that when I did this work daily and was asked to do side jobs I didn't really want to.
I have the confidence to do the job safetly and correctly. I wouldn't take it on if I didn't feel good about it. I just had a few questions and wanted to check with those who had more knowledge to varify my plans.
My plans we correct aside from conduit size and ground wire size. Neither of which would have posed a code or safety threat.
Thank you guys for your time.

wirenut1110 03-01-2009 07:50 AM

Don't forget about that no more than 360 deg in bends without a pull box, fitting etc. Conduit needs to be strapped within 3' of a box/fitting and within 10' thereafter. Again, code is minimum so if you want more support, feel free to do so.

If you have any more questions, feel free to ask.


All times are GMT -5. The time now is 07:31 PM.