This 5800 sq home has a main panel with no main breaker, a 100 amp sub panel, and a disconnect only box. Is it required that a main breaker be installed or can the lever type disconnect be an alternative? How would you word this?
We could not open the smaller lever disconnect box so I will state as such.
On the main panel what kind of verbage would you use for the main alumimum 4/0 wire that was spliced at the end just before reaching the lug. looks like the elec. was not skilled enough to fit it into the lug. The buyer claims that the panel has lost it’s rating because of this. I believe so but had not seen this.
NEC 408.36
IN addition to the requirement of 408.30, a panelboard shall be protected by an overcurrent protective device having a rating not greater than the panelboard.
So if there is no over current protection then the panel is wrong. Also if the wire has been cut to fit the lug then it is derated and not suitable for the panel.
The panel board requires over-current protection. The service disconnect for the structure is not required to be a “breaker” or “over-current device.” Apples & oranges.
I understand that, but if the wires go straight from the switch to the panel board, then from the pics it appears there is no applicable overcurrent protection for the main panel…
Correct??
Could be, but I wouldn’t bet on it. The conductors in the larger disconnect seem to be the same size as the conductors in the panel. The smaller disco to the right is a 100 amp and it’s likely that #4/0 conductor wouldn’t even fit in the lugs. There is a smaller enclosure to the right of the panel in photo #3 maybe the small disco feeds that. Either way the MLO panel with a non fused disconnect are a violation.
Shouldn’t the interior main panel have a main disconnect because it looks like more than 6 hand movements to power down the panel or is the external switch consider the main disconnect.
Yes, they were 4/0 alum in the panel and also in the lg. disconnect.
The 4/0 conductor would fit. Just one of the wires is cut and the other lug is the same size but not “beaten” up like the one with the wires cut.
Is it ok for the 100 amp for the sub to be in the main panel? I have always seen it in the main.
The wall that the throw’s are on is a detached 150-200sf office that has it’s own smaller AC. I am thiinking the smaller throw is tied into this building.
No. The switch does not provide over-current protection.
You guys are really making this confusing by not using the proper terminology.
Forget the terms “main panel” and “main disconnect.” The exterior panel is the “service” panel, which is where the “service” disconnect is located. All other panels are “load-side” equipment - call them sub-panels, distribution-panels, equipment-panels, lighting-panels, even just “panels.”
The rule applies to service equipment. The interior panel is not the service equipment.
I don’t know what you’re asking here. The 100 OCPD can be located in the service equipment. If the distribution panel is in the same building, there is no need for an additional OCPD.
No…
its pretty simple.
The service disconnect is just what it is… A disconnect, and not overcurrent protection. (I E cicuit breaker)
The panel itself needs some type of breaker between the disconnect and the panel. No matter if its a main or sub, somewhere at the begining it must have overcurrent protection.
If the "service disconnect were fused, then that would serve the purpose. Since it is not, and no other exists between it and the panel, in theory, then IT IS WRONG!!!
If you can find one then great, but if not it needs fixin!
So… since there is no breaker at the panel or sub panel to provide “over current protection” for the panel then it is wrong unless…there is a fused over current at the small throw box.
In other words the throw boxes just act a “service disconnect”.
I don’t know what you’re asking here. The 100 OCPD can be located in the service equipment. If the distribution panel is in the same building, there is no need for an additional OCPD.
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So it does not matter if the 100 amp breaker for the sub panel can be located in the panel or sub panel?
You need some sort of OCPD to protect the ungrounded service conductors. This could be one device or up to six devices if the 6 devices meet the parameters spelled out in 230.90(A)Ex#3. One device would need to be sized according to the ampacity of the service conductors. In this case #4/0 Al is permitted to be protected at 200 amps by 310.15(B)(6). Since in this installation there is no one OCPD for the service conductors then up to 6 devices grouped together can be used to provide the protection. The ampacity sum of the up to 6 devices can be greater than ampacity of the service conductors but the calculated load cannot exceed the ampacity of the service conductors.
Since this panel has more than 6 circuit breakers it would require a single OCPD for the protection of the service conductors. 240.21(D) takes us to 230.91, 230.90 also applies. The OCPD should be located within the service disconnect or immediately adjacent to it.
