Spare capacity in panelboards

[mc5w]

Re: Spare capacity in panelboards

However. local rules can say otherwise. In the Empire of Akron, Ohio ( refers to having to annex to get city water for fire protection ) a residential panelboard must have a minimum of 16 circuit breaker slots for branch circuits. Also, minimum grounding electrode conductor size is #4 solid copper or #2 stranded copper which gets rid of mechanical protection arguments not that there are a lot of 200 amp residential service upgrades.

Likewise, about 1/2 of the cities in the Cleveland, Ohio area have outlawed 15 amp wiring. I get less stock gragmentation if I do not stock 15 amp wire and I only need to remember 1 set of box fill and Scotchlok(R) fill calculations.

If I need to economize on wire for a 3-way/4-way circuit that has say 6 switching locations I can just as easily stick in a 24-volts circuit and a relay. Honeywell makes a combination transformer and relay on a 4x4 plate that is commonly used to control circulator motors on forced hot water heating systems. It has 12 amp inductive contacts in single pole double throw and double pole double throw configurations. Generally, a 12 amp inductive contact can run 8 amps of incandescent lighting based on motor versus tungsten filament inrush/locked rotor figures.

 

[LarryFine]

Re: Spare capacity in panelboards

Originally posted by mc5w:
If I need to economize on wire for a 3-way/4-way circuit that has say 6 switching locations I can just as easily stick in a 24-volts circuit and a relay. Honeywell makes a combination transformer and relay on a 4x4 plate that is commonly used to control circulator motors on forced hot water heating systems. It has 12 amp inductive contacts in single pole double throw and double pole double throw configurations. Generally, a 12 amp inductive contact can run 8 amps of incandescent lighting based on motor versus tungsten filament inrush/locked rotor figures.

Make sure it's listed for the use, which is a generic NEC requirement.

 

[lady sparks lover]

Re: Spare capacity in panelboards

Can I add to the discussion...

As good design practice, I go for 10%. That's what I learned in school, and that's how they do it here. My boss says the same, that it's in the NEC, but that's something I dispute. I think it's in the NEC to leave some extra spare compacity, but not the 10%.

Lady

 

[don_resqcapt19]

Re: Spare capacity in panelboards

Lady,

I think it's in the NEC to leave some extra spare compacity, but not the 10%.

Where?
Don

 

[ryan_618]

Re: Spare capacity in panelboards

Originally posted by LarryFine:
Make sure it's listed for the use, which is a generic NEC requirement.

Where?
Ryan

 

[lady sparks lover]

Re: Spare capacity in panelboards

Originally posted by don_resqcapt19:
Lady,

I think it's in the NEC to leave some extra spare compacity, but not the 10%.

Where?
Don

Not sure, I'd have to look that up. However, I know the 10% is something that was made up.

I think like someone said it should be a FPN.

This is all I found..

90.8 Wiring Planning.

This is from the handbook, but tell me what you think.
The requirement for providing the exclusively dedicated equipment space mandated by 110.26(F) supports the intent of 90.8(A) regarding future increases in the use of electricity.
Distribution centers should contain additional space and capacity for future additions and should be conveniently located for easy accessibility.
Where distribution equipment is installed so that easy access cannot be achieved, a spare raceway(s) or pull line(s) should be run at the initial installation, as illustrated in Exhibit 90.2.

Lady

[ May 26, 2005, 10:22 AM: Message edited by: lady sparks lover ]

 

[infinity]

Re: Spare capacity in panelboards

Lady,

Spare spaces in panelboards are not required by the NEC. 90.8(A) doesn't even mention panelboards and contains no language that would require spare spaces in them.

 

[charlie]

Re: Spare capacity in panelboards

Lady, I think you are correct but you reference is not correct. I am guessing the you were taught the 10% rule either in school or from your employer as a good design rule (which I agree with). However, the Code does not require any spare spaces in panelboards, extra conduits, extra cubic inches in boxes, etc.

 

[lady sparks lover]

Re: Spare capacity in panelboards

Originally posted by charlie:
Lady, I think you are correct but you reference is not correct. I am guessing the you were taught the 10% rule either in school or from your employer as a good design rule (which I agree with). However, the Code does not require any spare spaces in panelboards, extra conduits, extra cubic inches in boxes, etc.

[ May 26, 2005, 12:01 PM: Message edited by: lady sparks lover ]

 

[petersonra]

Re: Spare capacity in panelboards

Meeting minimum code requirements does not necessarily mean that you will meet all the requirements of a particular project.

Accounting for future needs in a cost effective way is one of these areas.

I would not want a system installed that had no capacity for future growth, as there is always future growth.

But I also do not see the need to install spare CBs, as long as there are spare slots available, or it is relatively easy to add another PB off an existing one (just as an example). It would be nice if the guy that came up with the original sizing made the incoming feed large enough to support reasonable future needs.

OTOH, it's not reasonable to expect a designer in 2005 to know what might be needed in 2010.

This is mostly a judgement issue, and IMO it is best left there.

 

[lady sparks lover]

Re: Spare capacity in panelboards

Originally posted by petersonra:

OTOH

OTOH??

 

[roger]

Re: Spare capacity in panelboards

Patricia, it's On The Other Hand

Roger

 

[69boss302]

Re: Spare capacity in panelboards

Maybe a different twist to the same subject, but what bothers me on these lines, is when engineers just blatantly say that there is extra room to expand designed into the system and they don't even check to see if it really was or possibly that "extra" has already been used for a different project. Why can't it be physically looked at before hand, I mean even if you as an engineer feel it's not up to you to go out to the site and check, you could assign somebody to.

I can't tell you the funny looks I've gotten when some engineer tells me, "We are putting this machine here and you just run power from this panel." and my response is "If you want it off that panel, what things do you want taken off?" They didn't do a proper load calculation or think to look. Usual response is "Just do what you need to do!" When I give them the order for new panel's feeds and services they just about drop. Then it's can't you cut this corner or that corner. Your the electrical guy "JUST GET ME ELECTRICITY". What am I supposed to do, buy a squirrel and a wheel and attach it to a generator right there for their personal use.

Why has it gotten to where no one else even thinks about the electrical end of things, just electricity is right there and you just tap into it, what's the big deal?

Well again, I ramble and am carrying of on a tangent so I will end this ranting.

Good Day. Keep smiling they'll think something is terribly wrong with you.

 

[lady sparks lover]

Re: Spare capacity in panelboards

Originally posted by 69boss302:
Good Day. Keep smiling they'll think something is terribly wrong with you.

Sounds like you need a hug!!!

 

[69boss302]

Re: Spare capacity in panelboards

Originally posted by lady sparks lover:

Originally posted by 69boss302:
Good Day. Keep smiling they'll think something is terribly wrong with you.

Sounds like you need a hug!!!

I'm not to sure I've ever known an engineer that knew how to ask nice

Or maybe I'm just to obnoxious myself to often, reality check time

[ May 26, 2005, 05:23 PM: Message edited by: 69boss302 ]

 

[jwelectric]

Re: Spare capacity in panelboards

Originally posted by iwire:
Any chance Mike was the instructor?

Should I be offended by this or not?

When I cover article 90 in a class room I make sure to point out that it is an Introduction to the chapters that are to follow as outlined in; (90.3 Code Arrangement, This Code is divided into the INTRODUCTION and nine chapters.) I am also sure to point out that the only part of article 90 that is mandatory is 90.9 Units of Measurement.

When instructing an inspector class I teach them to stay away from 90.4 unless they run across a contractor that is totally asinine, in which case, by all means use;

The authority having jurisdiction for enforcement of the Code has the responsibility for making interpretations of the rules, for deciding on the approval of equipment and materials,

Which even a child can decern as explaining the intent of the article.


[ May 26, 2005, 05:47 PM: Message edited by: jwelectric ]

 

[iwire]

Re: Spare capacity in panelboards

Originally posted by jwelectric:

Originally posted by iwire:
Any chance Mike was the instructor?

Should I be offended by this or not?

Your right, that was inappropriate.

Originally posted by jwelectric:
When instructing an inspector class I teach them to stay away from 90.4 unless they run across a contractor that is totally asinine, in which case, by all means use;

The authority having jurisdiction for enforcement of the Code has the responsibility for making interpretations of the rules, for deciding on the approval of equipment and materials,

Which even a child can decern as explaining the intent of the article.

Where I live 90.4 has been amended, the local inspector can not make interpretations of the code.

Also in MA, 90.6 has been amened to explain that interpretations come from the Board of Fire Prevention Regulations and I could appeal their decision to the Board of Electricians?.

 

[dillon3c]

Re: Spare capacity in panelboards

Howdy JW,
I see you read through this thread,and I think you might know where,and when this article/section was pointed out to me..Same group was present+1 of said jurisdiction + others, next stop "westerly direction".

This thread kinda-got a little turned around on me and never ment, to imply your class either..
-somehow I think you know that-

(Oh,ninesixtwofive,*1st/fumbling for the lighter )..(grin'in)
-->dillon3c-(thanx MW)

[ May 26, 2005, 08:59 PM: Message edited by: dillon3c ]

 

[john m. caloggero]

Re: Spare capacity in panelboards

OK Gentlemen: let's put it to bed!, I was staff liaison for Code-Panel 2. It was not the intent of the Code-Panel to require more circuit spaces in a panelboard than what the calculation in Article 220 required. However, as an electrician for many years, I would advised my customers that it was a money saver to have a panelboard with extra spaces in case they wanted to add additional loads. You have to be a sales person and consultant, as well as electrician!!!

 

[dillon3c]

Re: Spare capacity in panelboards

Originally posted by john m. caloggero:
OK Gentlemen: let's put it to bed!

OK...works for me Mr.Caloggero sir..

You have to be a sales person and consultant, as well as electrician!!!

Doesn't hurt to be a author either I guess..And I do like your current text sir..