ECN Forum
Posted By: shortcircuit Panelboard vs Load Center - 12/02/04 12:12 PM
In the 120/240 volt 400 amp or less single phase class,what are the advantages of useing a panelboard as opposed to a load center?

Posted By: slumlordworker Re: Panelboard vs Load Center - 12/02/04 02:01 PM
panelboards consist of assemblies of overcurrent protective devices with or with our disconnecting devices all placed in a metal cabinet are mainly used on larger commerical and industrial applications . these are usually raw and unpainted

load centers typicaly are fused or circuit breaker cabinets used on reasidental and light commerical projects. usually they are painted and come with trim for both styles of mounting

imo the advantages and disadvantage would depend on the installation application
most say they are one in same but really they are just a tad different
Posted By: JBD Re: Panelboard vs Load Center - 12/02/04 03:13 PM
Technically there is no such thing as a "loadcenter". What our trade calls loadcenters are still UL Listed as panelboards. The residential/commercial loadcenter is really nothing more than a marketing phrase.

Some manufacturer have large differences between their loadcenters and panelboards. They then create pricing and marketing to exploit these differences. This marketing has caused many electricians and, sadly, inspectors to believe there are restricted use issues with loadcenters.

First you must always follow the job specification, but after that the NEC doesn't care what the panel is called as long as it is an NRTL Listed panelboard.

In reality, the biggest difference between loadcenters and panelboards is the enclosure.

Panelboards enclosures usually included NEMA 12 and NEMA4/4X enclosures as well as the NEMA1 and NEMA3R offered in loadcenters.
Loadcenter back boxes are usually designed to fit inside the stud space of standard 2x4 wood frame construction and include knockouts located "conviently" for NM cable. Panelboard boxes are designed wider and deeper with very few knockouts to allow for many more conduit entrances.

Other than the enclosure and factory installed options, the differences can be very subtle, but it depends on the manufacturer. My experience has been that there are only a few general panelboard specs that are not offered in any loadcenter (i.e. bolt-on breakers).

For design and build projects, I have always based my choice of a Square D QO loadcenter or NQOD panelboard primarily on mounting and wiring considerations.
Posted By: shortcircuit Re: Panelboard vs Load Center - 12/02/04 06:06 PM
JBD...thanx for the input...the tip about more room for conduit entries with a panelboard is something I will consider in my decision on whether to use a load center or panelboard.

I have seen a load center fail where the breaker plugs into the bus many times...melted breakers didn't make a good connection to the panel bus.I've seen mains burn out in ITE load centers that were just plug in the mains come bolted in.

I think I feel more comfortable with a panelboard with bolt in breakers because of the heavier loads in a commercial installation.

Posted By: Electricmanscott Re: Panelboard vs Load Center - 12/02/04 10:51 PM
$$ [Linked Image]
Posted By: Sandro Re: Panelboard vs Load Center - 12/02/04 11:34 PM
Equally a concern as well, is the number of service calls I've had with bolt-on breaker issues. The breaker screws were either loose, or the installer forgot to tighten them at all.
Posted By: golf junkie Re: Panelboard vs Load Center - 12/02/04 11:49 PM
The biggest difference is physical size.

A panelboard gives you more working room and bending space for conductors.

A loadcenter will fit in a 3.5" deep stud space while a panelboard needs 5.5".

The OCPD devices are similar in both.
Posted By: shortcircuit Re: Panelboard vs Load Center - 12/03/04 02:15 AM
Electricmanscott...$$$.. Got prices today for a 400 amp ITE Load Center with main @$1270
and a ITE 400amp Panelboard with main breaker kit @ $650

Guess they don't sell to many 400amp loadcenters [Linked Image]

Posted By: caselec Re: Panelboard vs Load Center - 12/03/04 02:47 AM
If you can wait a few weeks I would suggest ordering a factory assembled panelboard which is usually quite a bit less expensive than ordering the individual components from your distributor and assembling them yourself. They can usually get you the can in a few days then will deliver the interior and front at a later time. The biggest savings ordering it factory assembled is the cost of the branch breakers. I have compared the prices of factory assembled to field assembled several times and the factory assembled is often about 50% less.

If this panel is for residential use where most of the circuits are going to be cable you might want to get the can with ko’s but if the circuits are going to be in raceways order it with out ko’s. If you use Square D the standard cans have ko’s on one end and are blank on the other end but you can specify otherwise.

Posted By: mhulbert Re: Panelboard vs Load Center - 12/03/04 03:36 AM
Are factory assembled usually cheaper for Square D NQOD??? I have a customer (the cost is not a big deal one from my last post) that wants to use the bolt-on panels in his home. Doing a service upgrade to 400A moutning 2 panels inside with the meter-main outside. I've never used NQOD before, what is the best way to go??? I figured the custom built one's would take a long time and cost more, am I wrong?
Posted By: JBD Re: Panelboard vs Load Center - 12/03/04 03:24 PM
I have noted most people talk about using bolt-on breakers with panelboards versus plug-on ones with loadcenters. Simply asking for a panelboard design does not guarantee bolt-on breakers. If you want bolt-on you must specify it,

My experience with Cutler Hammer CH and Square D QO breakers has been far fewer failures do to plug-on connections than with loose/stripped/cross-threaded connections when using bolt-on breakers.

I trust a factory built plug-on jaw more than an incorrectly field installed screw connection. But I do understand the concerns with the reinstallation of breakers and with "cheap" designs (i.e. FPE) especially on some aluminum bussing (i.e. Zinsco).
Posted By: golf junkie Re: Panelboard vs Load Center - 12/03/04 11:15 PM
"My experience with Cutler Hammer CH and Square D QO breakers has been far fewer failures do to plug-on connections than with loose/stripped/cross-threaded connections when using bolt-on breakers."

My experience is exactly the opposite! I've seen many plug-on breakers that have burned the breaker and buss bar beyond use. But I've never seen a bolt on fail.

If the bolt-ons are loose or stripped that sounds like a workmanship issue. Bolt-ons are definitely not as "user friendly", but that really shouldn't be an issue for a pro.
Posted By: electure Re: Panelboard vs Load Center - 12/04/04 12:25 AM
I'm with the Golf Junkie.
I've had very few failures with bolt on C/B's, and lots with plug-ins, except JBD's favorite - QOs (JBD, I love SqD stuff) The bolt on failures have been poorly installed, either loose or cross-threaded so as to seem as if they're torqued down, even though the connection is still loose.
It hasn't been limited to field installed breakers.
Try taking a torque driver to a factory assembled panelboard sometime. (well, everytime, actually) You might by pleased, or maybe disgusted. Don't trust 'em.

I think Caselec's got the best option, if you can hold out for the leadtime go for the factory assembled version>
Posted By: Scott35 Re: Panelboard vs Load Center - 12/04/04 07:21 AM
I was once asked by a Foreman:
"What's The Difference Between A Load Center And A Panelboard?"
(BTW, the "Question" was posed in a "Loaded Question" format - I.E. the Foreman already had an answer, but it did not match mine...).

The only thing I could think of was the Depth / Width dimensions of the Can (Enclosure).

Figuring I must have come close to a satisfactory answer, along with not being aware of the "Loaded Question" scenario (until my response was ... "De-Bunked"...), my jaw dropped rapidly to the floor upon the resultant corrections applied with the Foreman's rebuttal of:

"No!!! The Difference Is Load Centers Use Plug-On Breakers, And Panelboards Use Bolt-On Breakers".

Being the Glutten for punishment that I am, what do I do now???... of course - point out the "Semi-Obvious" information:
[Linked Image]

  • NEC has no definition or constraints towards the term Load Center, but the term Panelboard is vastly used,
  • Most Catalogs describe Equipment of 225 Amps and less, at 250 VAC maximum; which reside within Metallic Enclosures having dimensions that allow for flush mounting in the typical 2" x 4" @ 14.5" finished Wall Cavity, as a Load Center, whereas Panelboards typically have 20" wide x 5.75" deep Enclosures,

And the biggest "Clinchers" of them all:


[*] Most Load Centers may be ordered with either option for OCPD Terminal Mounting scheme: Bolt-On Bus or a Plug-On Bus,

[*] Square D Bus Kits are optional both ways - either use QO Plug-On Breakers, or remove the "Plug-On Stabs" from the Bussing and install QOB Bolt-On Breakers - commonplace for Panelboards and Load Centers.

Without going into full details, as to the reply from said Foreperson in rebuttal to the items above, let's just say I found out three things about myself which I did not know until that day:


[*] I know nothing about Electrical Systems, Systems Designs, Materials, Manufacturers Data, or anything related to the "Commonly Known Stuff That All Electricians Know",

[*] The fact that I was unaware of Panelboards vs. Load Centers means I will NEVER be any good as an Electrician - and impossible to even think of shooting towards being an Engineer,

[*] I am the least knowledgable Person in the Trade, have no NEC knowledge, never specified or even ordered Equipment, and I am the laughing stock on the job because of this.

This excitement took place exactly One Year and Two Months ago from this very Day, on a Public Works project which I was pulling a "Triple Threat" type working deal on
(Project Manager, Journeyman Installer, Revised installs FWO plans drawing / engineering / submission - shop drawings + record drawings... all at the same time).

Sorry to vent this here, and as you can see I still have issues over this.

Anyhow, AFAIK, the only difference between them is what you call them - Load Centers or Panelboards.
I prefer "Panelboards" and use the term as default to describe any OCPD assembledge cabinets that do not "Qualify To Be Defined As Switchgear", and contains MCCBs - but not Fuses or Fusible Switches.

As to the failures of Terminations (Plug-On vs. Bolt-On), I have seen a Hand-Full of failed Bolt-On scenarios - commonly from stripped threads on thin Aluminum Busses or other loose Terminations at the Bus.

On the other hand, have shot trouble + repaired many, many, many-many-many "Barbeque Scenarios" oriented around Plug-On Bussing issues, as applied to heavy, continuous Loads.

On this subject, I have a Red Wirenut which is fried, due to a poor makeup situation. Found it a few Months back during the Demolition part of a T.I. Project.

I'll post an image + story later in the Photos Forum.


P.S. Please excuse any spelling air-ors (errors).
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