Building specifications no wire smaller than number 10 CHW

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wyreman

Senior Member
Location
SF CA USA
Occupation
electrical contractor
There's a big argument over here on this job over the specs.
This large project
there is no wire allowed smaller than number 10
No stranded. Has to be solid.
Also no pipe smaller than 3/4" emt

Some people say this is a complete waste of resources and
some people say this is the mark of a really excellent job.
What do you guys think?
 

dicklaxt

Senior Member
Ouch, #10 mimimum,,,,,,,,,out of curiosity what type of complex? 3/4" is pretty standard in industry at least Petro Chem,Refinery,Plastics,Fertilizer etc,not sure about manufacturing.

dick
 

barclayd

Senior Member
Location
Colorado
I first saw a standard like this years ago when I job-shopped at IBM. Their 'reasoning' for the 3/4" was to allow more diversity when changes had to be made. In the several decades since then, I have NEVER seen that actually happen. Whenever 'changes had to be made', they always included ripping out everything and starting over.
For a 20 amp circuit, three #10's in a 3/4" is absurd. Three #12's in a 3/4" is just slightly less absurd.
I always spec. stranded wire for use in flexible conduit, otherwise solid is ok.
In my opinion, the #10 & 3/4" standard is a waste of money.
db
 

renosteinke

Senior Member
Location
NE Arkansas
I have a customer, a steel mill, that want everything in rigid (I expect IMC would be OK) and 3/4 minimum.

It's their money. It's our job to make them happy.

More to the point, they might know something you don't. Their past experience, and what they want to stock as maintenance parts, come into play. Also, they may have had a bad experience with someone, and want nothing to do with that guys' methods.
 

wyreman

Senior Member
Location
SF CA USA
Occupation
electrical contractor
I stated it wrong, no wire smaller than number 8 can be stranded.
Institution of higher learning =)
 

Ponchik

Senior Member
Location
CA
Occupation
Electronologist
Unless it is needed to be #10 solid, I think it is waste of resources, money & labor. It is probably some else's money that is being spent.

Is is specified and required per city or per engineer? Sometimes San Francisco has wacky requirements.
 

G._S._Ohm

Senior Member
Location
DC area
Being flexible allows a person to adapt to whatever life throws at him/her
and
being able to design a system with a wide range of materials allows the EC to better meet the demands of the future.

This rule limits flexibility.

I hope they have a good reason for it. It almost comes down to them believing that they can predict the future.
Narcissistic.:thumbsup:
 

GUNNING

Senior Member
MERRY Christmas!

MERRY Christmas!

So why not put in what they ask for? It sounds good to me. The more it costs the more I make.
Adjust your attitude and those around you to what is being paid for. DO NOT THINK, just do it, and charge accordingly.

When others start making pronouncements like "This isn't right and a waste of money", I'm thinking burnout case. Someone that is having mental difficulties coping and insulting my customer and there employment.

When someone asks for something like this I say three words "OK, sounds good", and nod with a smile. I give the benefit of the doubt that they know what they are talking about and know what they are buying from me and I am grateful for the work. :thumbsup:
 

G._S._Ohm

Senior Member
Location
DC area

dicklaxt

Senior Member
So why not put in what they ask for? It sounds good to me. The more it costs the more I make.
Adjust your attitude and those around you to what is being paid for. DO NOT THINK, just do it, and charge accordingly.

When others start making pronouncements like "This isn't right and a waste of money", I'm thinking burnout case. Someone that is having mental difficulties coping and insulting my customer and there employment.

When someone asks for something like this I say three words "OK, sounds good", and nod with a smile. I give the benefit of the doubt that they know what they are talking about and know what they are buying from me and I am grateful for the work. :thumbsup:


These Spec minimums are not mistakes or waste as some call it,,,,,,they are plant standards and they are correct in writing that in to meet their stds.Plant maintenance people are also okay with it, it's there's to do with as they see fit . I don't see this as a problem at all.I worked for different engineering companies in my career and most had their way of doing things as long as it met or exceeded safe and /or code compliance what's the beef. Everyone profits and prospers and goes to bed happy.

dick
 

Fulthrotl

~Autocorrect is My Worst Enema.~
There's a big argument over here on this job over the specs.
This large project
there is no wire allowed smaller than number 10
No stranded. Has to be solid.
Also no pipe smaller than 3/4" emt

Some people say this is a complete waste of resources and
some people say this is the mark of a really excellent job.
What do you guys think?

anyone who specifies solid wire is an idiot.

not judging, just reporting facts.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
IME a lot of places ban conduit under 3/4. I have no idea why but it is pretty common.

I have never run across a min#10 wire rule but min #12 is not unheard of. I have been told it is because #12 is much stronger then #14 and is less likely to fail while being pulled.

I wonder if the 3/4 conduit spec is to make sure the wires have plenty of pulling room as well.
 

rookie4now

Senior Member
We recently bid on a similar job. We bid exactly as requested and provided an alternate with #12. We were awarded the job with the #10 minimum even though the cost was higher. I still don't know why the designer felt that #10 was required, all I know is they were willing to pay for it and I feel I did my part by advising them of the additional cost. As far as the "solid only" I have no idea. I personally use stranded due to easier pulls. Sometimes we'll use stranded and solid to easily identify wires of the same color in the same conduit. I will throw out there that I have had engineers tell me that they like a little "cushion" and therefore specify a larger wire. I really feel this is wasteful. If you're going to use #10 as a cushion it isn't necessarily a better job. Based on that logic, why not use #8. A bunch of engineers have decided what the completely safe ampacity is for wire and I don't know why any "extra" needs to be added unless there are special circumstances. but in your particular case, none of that matters. Just quote what they are asking for and provide an alternate if you like.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
IME a lot of places ban conduit under 3/4. I have no idea why but it is pretty common.

I have never run across a min#10 wire rule but min #12 is not unheard of. I have been told it is because #12 is much stronger then #14 and is less likely to fail while being pulled.

I wonder if the 3/4 conduit spec is to make sure the wires have plenty of pulling room as well.

in control applications with pilot duty devices, #18 & #16 stranded MTW is very common.
i've never had a wire of ANY guage fail when being pulled, in 35 years.
 

PEDRO ESCOVILLA

Senior Member
Location
south texas
i used to do a lot of work in paper mills in new hampshire, some of it was maintenance and repairs for large ec contractor that did all the electrical as design /build . we always ran rigid, always pulled a ground, # 10 stranded for all circuits. it's what they wanted. alot of it had to do with atmosphere (rigid) and length of run from source to end of circuit (#10 wire).
 

iceworm

Curmudgeon still using printed IEEE Color Books
Location
North of the 65 parallel
Occupation
EE (Field - as little design as possible)
... I will throw out there that I have had engineers tell me that they like a little "cushion" and therefore specify a larger wire. I really feel this is wasteful. ....

Rookie -
I don't. I think you are wrong on this. I'm way past "wasteful". I'm thinking pure "stupidity". :dunce:

Somebody really needs to break their sliderules and get them banned from the secret engineer's meetings.:thumbsdown:

Yes, there are good reasons to overdesign some aspects of a job. This is not one. Good heavens, "a little cushion" - :sick: puke

ice
 

cdslotz

Senior Member
There's a big argument over here on this job over the specs.
This large project
there is no wire allowed smaller than number 10
No stranded. Has to be solid.
Also no pipe smaller than 3/4" emt

Some people say this is a complete waste of resources and
some people say this is the mark of a really excellent job.
What do you guys think?

What is to argue?
Specs are specs. They say what they require....period.....end of story.
It doesn't matter what your opinion is.

I have to ask, were you awarded this large job after you bid it in #12 and 1/2" EMT?
 
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