200 & 200 dosen't = 400

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jetlag said:
Back then you could run as far as you wanted from the meter to the panel with no disconnect in between . Where they went wrong was installing the 400 amp disconnect . They could have ran the se to both panels if they had used 200a main breaker panels ,and now it would be grandfathered in . But back then they didnt inforce the 4 wire from a disconnect either and thats a big problem for you now. (I will add the box with the heat is not required to be 4 wire if it contains only 240 circuits). If you must have the 400 amp I believe you will have to start over all the way from a 400 meter socket designed for 2 - 200 amp disconnects.
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A 400 amp disconnect is rated for 200 amps, and then some, you just need to fuse it correctly. like Jim said,"do a load calculation." If the load is under 200 amps on each panel, whats the problem?
 
Hendrix said:
I just saw a residential service wired in 1969 (and inspected). From the metersocket came two pieces of 4/0 SEU to two 400 amp fuses inside a 400 amp switch. From there two pieces of 4/0 SEU continue to two sub panels with 200 amp main breakers.
Could this have been legal in 1969 :D I asked a couple of "old timers" about this inspector (he left a inspection certificate with his name on it stapled to the panelboard) they remember his not allowing 14/2 romex or 1/2 inch emt also.:confused:
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it is possible that the inspector in 1969 was making up his own rules since in new hampshire there was no Electrician license they did not licenes untill 1976 so there is no telling whether or no they were following the 1968 NEC at that time or any code at all.
Is that 4/0 copper? if so its only good for a 250 amp service,,see table 310.15(B)(6)
:)
 
acrwc10 said:
A 400 amp disconnect is rated for 200 amps, and then some, you just need to fuse it correctly. like Jim said,"do a load calculation." If the load is under 200 amps on each panel, whats the problem?
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There is a lot of problems, the fuses can be no more than 200a , because that is the rating of each se to sub panel . If 200 amp was enough I doubt they would have installed a 400 a disconnect . The install does not meet the reqirements for tap conductors ..They are planning to add more loads . If the total load calc for house is over 200 a , no go . This install is the same as connecting 2 -15a circuits to a 30 a breaker with # 14 conductors , it does not matter if each load is under 15amp . Can only use a 15a breaker.
 
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jetlag said:
There is a lot of problems, the fuses can be no more than 200a , because that is the rating of each se to sub panel . If 200 amp was enough I doubt they would have installed a 400 a disconnect . The install does not meet the reqirements for tap conductors ..They are planning to add more loads . If the total load calc for house is over 200 a , no go . This install is the same as connecting 2 -15a circuits to a 30 a breaker with # 14 conductors , it does not matter if each load is under 15amp . Can only use a 15a breaker.
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Maybe I am not visualizing this install correctly. I read it as one 400 amp meter socket with two 400 amp fused disconnects, each feeding a 200 amp MLO panel. If this is what it is then changing the fuses down to the correct size for the conductors is no problem, it is far better then an oversized fuse.
Now on the other hand if this is a single fused disconnect, it is time to change out to a pair of disconnects.
 
acrwc10 said:
Maybe I am not visualizing this install correctly. I read it as one 400 amp meter socket with two 400 amp fused disconnects, each feeding a 200 amp MLO panel. If this is what it is then changing the fuses down to the correct size for the conductors is no problem, it is far better then an oversized fuse.
Now on the other hand if this is a single fused disconnect, it is time to change out to a pair of disconnects.
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I understand it to be a single 400 amp disco with the conductors from 2 se cables attached to the same lugs . The se cables feed two 200 a main lug panels . The panels are to far away to count as tap conductors and they would also need a main breaker, also ser cable would be needed ,, it looks hopeless to me to try to save this install, I dont believe the meter socket is designed to attach two 200a conductors on the same lug so that would need to be changed to install 2 -200 amp disconnects , then an ser cable to each panel should bring it up to code , even without a main breaker in the panels.
 
jetlag said:
I understand it to be a single 400 amp disco with the conductors from 2 se cables attached to the same lugs . The se cables feed two 200 a main lug panels . The panels are to far away to count as tap conductors and they would also need a main breaker, also ser cable would be needed ,, it looks hopeless to me to try to save this install, I dont believe the meter socket is designed to attach two 200a conductors on the same lug so that would need to be changed to install 2 -200 amp disconnects , then an ser cable to each panel should bring it up to code , even without a main breaker in the panels.
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Not on a true 400 amp meter, at 320 continuous meter (plug in type) you might find one rated for two conductors in a single lug. But at 400 amps continuous it will have CT's on it.
 
acrwc10 said:
Maybe I am not visualizing this install correctly. I read it as one 400 amp meter socket with two 400 amp fused disconnects, each feeding a 200 amp MLO panel. If this is what it is then changing the fuses down to the correct size for the conductors is no problem, it is far better then an oversized fuse.
Now on the other hand if this is a single fused disconnect, it is time to change out to a pair of disconnects.
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Why would you need or want 2 disconnects ? All it needs is to be fused at 200 amps. Now if computed load is over 200 then we have a problem
 
The total load must be under 200 amps because the fuse needs changed. Would seem like if its been ok for this many years that load is ok or we would have damaged wires. Now if your adding more loads then be carefull. This does not need to be a costly fix.
 
Hendrix said:
One of the panels is filled with electric heat.
Problem is, the electrician is adding new circuits so........I'm asking to bring the whole thing up to code. What would you do?
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The problem with grandfather laws is it doesn't matter what the code says in the 1969 code book, since this service was inspected at the time, it would now depend upon what NH or the local jurisdiction adopted into law and required at the time.

But any additions to an existing system can not make the existing system against code so now you have to figure if these new circuits would exceed what was originally allowed?

I think a load calculation is in order, also since these are sub panels look out for 3-wire range and dryer circuits, never allowed even back then from a sub panel, but again this would be dependent upon what was required, that inspection ticket is the out they can use in court if they want to challenge it, if this installation was allowed by NH codes in 1969.
 
jetlag said:
I understand it to be a single 400 amp disco with the conductors from 2 se cables attached to the same lugs . The se cables feed two 200 a main lug panels . The panels are to far away to count as tap conductors and they would also need a main breaker, also ser cable would be needed ,, it looks hopeless to me to try to save this install, I dont believe the meter socket is designed to attach two 200a conductors on the same lug so that would need to be changed to install 2 -200 amp disconnects , then an ser cable to each panel should bring it up to code , even without a main breaker in the panels.
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That's the way I see it also:)
 
acrwc10 said:
I basically said that in post 21.
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We all pretty much agree on that, the question is if 200 amp was enough why did they run 400 amp in , Im thinking it is avery large house and if they needed a seperate 200 amp panel for the heat it must have seperate baseboard or wall heat in every room , that can put the load calcs over 200 very easily on a large house. The load does not have to be enough to damage wires to be an illegal install. They are also adding more loads
 
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lakee911 said:
What? Can't feed a dryer or range from a subpanel? Why not?
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Lakee, you need to quote who are are referencing when you type something that is a few posts remove from your response. It helps us know what you are talking about. I finally found the reference in Waynes post.

Wayne is referencing the use of a 3 wire range or dryer that typical was installed with an seu cable. That was allowed but it had to be fed from the service panel. If it had an insulated neutral then you could go to a sub panel. I think I have that right.

So when you make an existing main panel a sub panel then those circuits should be remove either back to the main panel or properly upgraded.
 
Dennis Alwon said:
Lakee, you need to quote who are are referencing when you type something that is a few posts remove from your response. It helps us know what you are talking about. I finally found the reference in Waynes post.
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Sorry. I usually do. Am on my blackberry...pain in the rear.

Dennis Alwon said:
Wayne is referencing the use of a 3 wire range or dryer that typical was installed with an seu cable. That was allowed but it had to be fed from the service panel. If it had an insulated neutral then you could go to a sub panel. I think I have that right.

So when you make an existing main panel a sub panel then those circuits should be remove either back to the main panel or properly upgraded.
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So if sub panel is in seperate structure from main, then no choice but to upgrade, no?

Do you have a code ref so I can go read? Thx
 
240 and 240 dont make 480 either lol. went to bid a job last week the guy said he had a cnc machine 480v. I told him he better be sure his building had 480, he said it did. When I got their I saw 2 30 circuit residential grade panels side by side, I thought dont look like 480 volt panels after looking at the main breakers and reading 240vac printed on them I informed him he didnt have 480. He said sure I do 240 and 240 is 480. Its always interesting what u run into out their lol.
 
lakee911 said:
So if sub panel is in seperate structure from main, then no choice but to upgrade, no?

Do you have a code ref so I can go read? Thx
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Heres the 2008 version:
250.140 Frames of Ranges and Clothes Dryers. Frames
of electric ranges, wall-mounted ovens, counter-mounted
cooking units, clothes dryers, and outlet or junction boxes
that are part of the circuit for these appliances shall be
connected to the equipment grounding conductor in the
manner specified by 250.134 or 250.138.
Exception: For existing branch-circuit installations only
where an equipment grounding conductor is not present in
the outlet or junction box, the frames of electric ranges,
wall-mounted ovens, counter-mounted cooking units,
clothes dryers, and outlet or junction boxes that are part of
the circuit for these appliances shall be permitted to be
connected to the grounded circuit conductor if all the following
conditions are met.
(1) The supply circuit is 120/240-volt, single-phase,
3-wire; or 208Y/120-volt derived from a 3-phase,
4-wire, wye-connected system.
(2) The grounded conductor is not smaller than 10 AWG
copper or 8 AWG aluminum.
(3) The grounded conductor is insulated, or the grounded
conductor is uninsulated and part of a Type SE serviceentrance
cable and the branch circuit originates at the
service equipment.
(4) Grounding contacts of receptacles furnished as part of
the equipment are bonded to the equipment.
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Pay attention to the highlighted in red above, many miss that.
 
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hurk27 said:
Heres the 2008 version:
250.140 Frames of Ranges and Clothes Dryers. Frames
of electric ranges, wall-mounted ovens, counter-mounted
cooking units, clothes dryers, and outlet or junction boxes
that are part of the circuit for these appliances shall be
connected to the equipment grounding conductor in the
manner specified by 250.134 or 250.138.
Exception: For existing branch-circuit installations only
where an equipment grounding conductor is not present in
the outlet or junction box, the frames of electric ranges,
wall-mounted ovens, counter-mounted cooking units,
clothes dryers, and outlet or junction boxes that are part of
the circuit for these appliances shall be permitted to be
connected to the grounded circuit conductor if all the following
conditions are met.
(1) The supply circuit is 120/240-volt, single-phase,
3-wire; or 208Y/120-volt derived from a 3-phase,
4-wire, wye-connected system.
(2) The grounded conductor is not smaller than 10 AWG
copper or 8 AWG aluminum.
(3) The grounded conductor is insulated, or the grounded
conductor is uninsulated and part of a Type SE serviceentrance
cable and the branch circuit originates at the
service equipment.
(4) Grounding contacts of receptacles furnished as part of
the equipment are bonded to the equipment.

Pay attention to the highlighted in red above, many miss that.
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Wayne how do you change the letters to red highlighted?
 
LEO2854 said:
Wayne how do you change the letters to red highlighted?
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At the top of the page after you click the
quote.gif
or
reply.gif
buttons, you will see a
color.gif


Now move you mouse pointer to the point in the words just left of the ones you want to highlight push the left mouse button down and drag over the words you want to change color, the let go of the left button, then go to the top and click on the
color.gif
arrow and select the color you want to highlight, once you do this it will use that color for the rest of that post untill you change it, it will take a little practice to get used to highlighting just the words you want to color be keep trying.

Also click on the side of
color.gif
button that has the arrow to change colors again in the same post.
 
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