Any issues with this installation?

[bjp_ne_elec]

Was pricing a house and notice the panel was full, and someone added a two circuit subpanel - and quess what - both circuits in the sub were loaded up. This panel is the old Westinghouse that has colored breaker handles - Red is 20 A, Blue is 15A, and I'm not sure what the other Amperages are, but remember a Green one. Electrical supply in town indicates that the Cutler Hammer BR series are the replacements for the Westinghouse.

The panel has 100 A Main, and if memory serves me right - there were three 2-pole breakers and then twelve single pole breakers. There were a set of lugs at the top of the panel - I assume tied directly to the bus. Whomever installed the subpanel, fed off the these lugs. It appears to be #8 AWG feeding between the lugs and the subpanel, which is MLO. And again, the panel only has two breakers.

First question, is this a legal installation as it stands?

The my next question involves taking out the two circuits subpanel and adding an eight circuit. There are several circuit breakers that have two wires in to them, which go off and feed two seperate circuits. The added breakers in the new subpanel will allow the circuits to be split up - and one thing I'll note, is that the total current draw is fine, considering the 100A main. Would this fall under the section in the code (this is kind of what I'm asking as to the first question - is the present installation legal) that covers taps - as far as feeding the new eight circuit panel via the lugs at the top of the panel.

Normally when I've added a subpanel, I've fed them off a two pole breaker in the main panel.

Thanks,

Brett

 

[Smart $]

...

First question, is this a legal installation as it stands?

...Would this fall under the section in the code ... that covers taps - as far as feeding the new eight circuit panel via the lugs at the top of the panel[?]

...

Yes, the installation falls under the tap rules. Assuming not more than 10 feet, as it is the installation is only legal by NEC 2005 if the #8 taps have an ampacity equal to or greater than the subpanel rating, since it has no ocpd at the tap conductor's terminations. Also the tap conductors must have an ampacity of not less than the combined calculated load of the circuits it supplies. Additionally, the tap conductors are required to be in raceway between tap and termination enclosure.

 

[hillbilly]

Yes, the installation falls under the tap rules. Assuming not more than 10 feet, as it is the installation is only legal by NEC 2005 if the #8 taps have an ampacity equal to or greater than the subpanel rating, since it has no ocpd at the tap conductor's terminations. Also the tap conductors must have an ampacity of not less than the combined calculated load of the circuits it supplies. Additionally, the tap conductors are required to be in raceway between tap and termination enclosure.

And that's also assuming that the tap is made downstream of the Main breaker. When you say that the tap is made at the top...Is that above or below the main?
just a thought
steve

 

[augie47]

sub-panel

sub-panel

I guess a liberal interpretaion of the Code might call this a two section panel. . I would not. To me 408.36 would apply requiring a main for the 2nd panel (at either location)

 

[jwelectric]

As I read the original post I start thinking that this in not a sub panel at all but instead a separate main panel in and of itself.

The panel has 100 A Main, and if memory serves me right - there were three 2-pole breakers and then twelve single pole breakers. There were a set of lugs at the top of the panel - I assume tied directly to the bus. Whomever installed the subpanel, fed off the these lugs. It appears to be #8 AWG feeding between the lugs and the subpanel, which is MLO. And again, the panel only has two breakers. First question, is this a legal installation as it stands? Thanks, Brett

How is the service conductors terminated in the first panel?
Do they terminate in a breaker or are they landing on the buses of the first panel?
Unless the service conductors land on an Overcurrent device in the first panel then the second panel is a service disconnect also.

Other questions that come to mind are;
Is the main in the first panel tied to the panel or is it just snapped in?
Does this breaker turn off all power coming in?
Is there four conductors to the second panel and are the neutral and equipment grounds separated?
How much is a dozen eggs in China?

A lot of unanswered questions here.

 

[Smart $]

And that's also assuming that the tap is made downstream of the Main breaker. When you say that the tap is made at the top...Is that above or below the main?
just a thought
steve

Well I assumed it had a main...

The panel has 100 A Main,...

a since the lugs were at the top, I assumed it was either a bottom, side, or a back-fed panel, with a feed-thru design.

 

[Smart $]

A lot of unanswered questions here.

...Well, I can answer one...

How much is a dozen eggs in China?

12

 

[hillbilly]

I guess a liberal interpretaion of the Code might call this a two section panel. . I would not. To me 408.36 would apply requiring a main for the 2nd panel (at either location)

Good call augie 47. The OP didn't state...but...If the tap panel has a neutral (grounded conductor) it is a lighting and appliance panel and must have it's own main disconnect. The tap rules are for the feeder conductors only [240.21(B)(1)]. What you feed with the taps may have different requirements in and of themselves. The type of panel that you're feeding (lighting and appliance) requires it to have a main. If the existing tap panel that you have is supplying a 230V load (without a neutral), and all of the other provisions of 240.21 are met, it's legal as is (if the tap is made downstream of the 100A main). If you replace it with another panel that has any loads requiring a neutral, the replacement panel must have it's own main disconnect (408.36), although you can still apply the tap rules to supply power to it.
Have you done a load calculation? You may need a service up-grade. If so, you can consolidate all of the circuits in one (larger) panel.
Just my opinion, hope it makes sense.
steve

 

[hillbilly]

Well I assumed it had a main...

Yes..the OP stated that it had a main. He also stated that he "assumed" that the tap conductors were attached to the bus (below the main I suppose).
I don't like to assume, although I will say this. I assume that if I don't assume anything at work today, I've got a better chance of making it home tonight.
George made a good point. That second panel (maybe) could be considered a
main panel in itself. If not, why not?
just discussing
steve

 

[bjp_ne_elec]

The "main breaker" in this situation is a plug-in on the bus - and this breaker is used to feed (consider this scenario back-feeding - at least the terminolgy that I grew up on) - so that would mean the main bus is running up the back of the primary panel, and the lugs would be attached to it.

So based on those facts, I think I'm reading that this would not fall under the tap rule, and the subpanel should have a Main Breaker - is this accurate?
Would one solution be to mount a 50A 2-pole in the subpanel and feed in to it? Or does it have to be protected at the point of origin - which would be out of the main panel? The issue with the main panel, is it's already "busting at the seams" as far as breaker space is concerned.

THanks

Brett

 

[Smart $]

The "main breaker" in this situation is a plug-in on the bus...

That's a problem. "...shall be secured inplace by additional fastener that requires other than a pull to release the device from the mounting means on the panel"?408.6(F).

This makes all other issues moot, IMO.

 

[hillbilly]

The "main breaker" in this situation is a plug-in on the bus - and this breaker is used to feed (consider this scenario back-feeding - at least the terminolgy that I grew up on) - so that would mean the main bus is running up the back of the primary panel, and the lugs would be attached to it.

So based on those facts, I think I'm reading that this would not fall under the tap rule, and the subpanel should have a Main Breaker - is this accurate?
Would one solution be to mount a 50A 2-pole in the subpanel and feed in to it? Or does it have to be protected at the point of origin - which would be out of the main panel? The issue with the main panel, is it's already "busting at the seams" as far as breaker space is concerned.

THanks

Brett

If I understand the situation correctly, consider this.
Since the existing 100A service is adequate (as you said) for the existing house load (and the additional load that you're going to add), why not install a 2 pole breaker (up to 100A max, whatever you need) to the existing panel and feed out to another (new) MLO panel (20 space?) that's mounted beside the existing panel. The feeder conductors need to be sized to the breaker that's feeding them. I would then move some of the existing circuits to the new panel and add any new circuits that I needed. The feeder needs to be 4 wire and the neutral isolated in the new panel (not bonded). Bonding for the new panel will be by the (new) grounding conductor that's contained in the feeder. Read Articles 215, 220, 250 and 408 in the NEC.
Tap rules do not apply in this scenario
You need to find and install a "breaker lock" (I don't know the correct name, but it locks the breaker in position so that you can't pull it out) for the existing 100A breaker that's being used for the main [408.36(F)].
If you can't find one (breaker lock) for the old panel, you may want to consider installing a new 100A main breaker panel instead of the MLO, splice the service entrance conductors to feed the new main and feed (with a breaker) the old panel from the new one.
This is only my opinion (and that's assuming that I understand the problem fully).
You need to read and understand the NEC articles that I posted so that you have a good understanding of what is required.
Use this information for reference only. You must be the judge (and the AHJ) as to whether your particular installation is safe and code compliant.
steve

 

[bjp_ne_elec]

OK - let's see if everyone gives this their seal of approval - the NEC is great, isn't it - it's interesting to see that we can not all agree to it's interpretation, but let's see if we can here.

1. The Main 100A breaker is a plug in, in the main panel, and to be legal by
today's 2005 NEC, it should be bolted down (I'm pretty sure, that it's just
sitting with a "plugged in" scenario and has no hold-downs) - yah or nay?
2. I should be fine if I feed the subpanel off a 60A 2-pole breaker plugged in
to the main panel, and feed the lugs on the MLO subpanel - yah or nay?
3. The present installation, with the subpanel being fed off the top lugs (so
they are "downstream" from the main breaker is illegal, as installed, per the
2005 NEC - yah or nay?
4. The neutral and EGC bus will be isolated in the subpanel - yah or nay?

Thanks,

Brett

 

[Cavie]

#1 - Yes

#2 - YES

#3 - ?

#4 - YES

 

[hillbilly]

OK - let's see if everyone gives this their seal of approval - the NEC is great, isn't it - it's interesting to see that we can not all agree to it's interpretation, but let's see if we can here.

1. The Main 100A breaker is a plug in, in the main panel, and to be legal by
today's 2005 NEC, it should be bolted down (I'm pretty sure, that it's just
sitting with a "plugged in" scenario and has no hold-downs) - yah or nay?
2. I should be fine if I feed the subpanel off a 60A 2-pole breaker plugged in
to the main panel, and feed the lugs on the MLO subpanel - yah or nay?
3. The present installation, with the subpanel being fed off the top lugs (so
they are "downstream" from the main breaker is illegal, as installed, per the
2005 NEC - yah or nay?
4. The neutral and EGC bus will be isolated in the subpanel - yah or nay?
Brett

Thanks,
IMO
1. yea
2. yea ...As long as the sub-panel is rated at least 60A. (The rating of the sub has to be equal to or more than the breaker feeding it)
3. nay. The present installation is legal [as long as all of the rest of 240.21(B)(1) is complied with], and the existing sub-panel doesn't have a neutral (408.34 & 36). With the 100A (main) panel being backfed thru a breaker, the bus bars (and the lugs that feed the sub) are protected by the backfed main breaker. Thus if you turn the main off, the bus bar is made dead...right? If so, it's OK. The tap rules apply.
4. yea
steve

 

[jwelectric]

OK - let's see if everyone gives this their seal of approval - the NEC is great, isn't it - it's interesting to see that we can not all agree to it's interpretation, but let's see if we can here. Thanks, Brett

I doubt it but we will try

1. The Main 100A breaker is a plug in, in the main panel, and to be legal by today's 2005 NEC, it should be bolted down (I'm pretty sure, that it's just sitting with a "plugged in" scenario and has no hold-downs) - yah or nay? Thanks, Brett

Any back fed breaker is required to be fastened to the panel by other than pull means

2. I should be fine if I feed the subpanel off a 60A 2-pole breaker plugged in to the main panel, and feed the lugs on the MLO subpanel - yah or nay? Thanks, Brett

Yes as long as the feeders are sized in accordance with the 60 breaker.

3. The present installation, with the subpanel being fed off the top lugs (so they are "downstream" from the main breaker is illegal, as installed, per the 2005 NEC - yah or nay? Thanks, Brett

As long as the feeders are sized by the device that protects them then, in this case a 100 amp breaker, the lugs on the main panel could be used to supply the sub panel

4. The neutral and EGC bus will be isolated in the subpanel - yah or nay? Thanks, Brett

The only place that the equipment grounding and the neutral can come in contact with each other is in the main panel.

 

[Smart $]

1. The Main 100A breaker is a plug in, in the main panel, and to be legal by today's 2005 NEC, it should be bolted down (I'm pretty sure, that it's just sitting with a "plugged in" scenario and has no hold-downs) - yah or nay?

aye

2. I should be fine if I feed the subpanel off a 60A 2-pole breaker plugged in to the main panel, and feed the lugs on the MLO subpanel - yah or nay?

aye

3. The present installation, with the subpanel being fed off the top lugs (so they are "downstream" from the main breaker is illegal, as installed, per the 2005 NEC - yah or nay?

tentative nay... 1) You never did say if the conductors, considered tap conductors in this situation, are run in raceway to the subpanel. They are non-compliant if they are not. 2) You did not divulge the maximum ampere rating of the subpanel. It is non-compliant if this rating is more than the ampacity of the tap conductors. 3) The subpanel/tap-feeder assembly is non-compliant if the combined loads served are calculated at more than the ampacity of the tap conductors, where "calculated" means whichever is greater: load calculated per Article 220 Parts I & II or actual load.

4. The neutral and EGC bus will be isolated in the panel - yah or nay?

aye

 

[bjp_ne_elec]

For clarification on #3 - the conductors are contained in an offset nipple, and are only #6 AWG - they are obviously not rated for 100A ampacity.

Thanks,

Brett

 

[jwelectric]

For clarification on #3 - the conductors are contained in an offset nipple, and are only #6 AWG - they are obviously not rated for 100A ampacity.

Thanks,

Brett

Copper or aluminum?
What type of insulation?

 

[Smart $]

For clarification on #3 - the conductors are contained in an offset nipple, and are only #6 AWG - they are obviously not rated for 100A ampacity.

Thanks,

Brett

They are tap conductors. If they had 100A ampacity, they wouldn't be tap conductors.