Sub question about isolation again!!


The exterior mains are outside at 100 amps. The subs are in the garage.

Are the nuetrals and grounds supposed to be isolated. Once again explain what can happen if not isolated.

Do you think there is enough pluged in to this outlet? Give me a break(er)
So I am not a very punny guy. Long day patients is shot I need a RR margaritaville.


Yes they have to be separate. The grounding conductors are required to be bonded to that panel as well.


If you are refering to the first (2) pictures it was obviously before the requirement for a 4 wire system on sub-panels. In this case it is clear their is a disconnect on the outside of the building and is in 3 wire…again probably complaint in the day it was done but not safe by todays standards.

While in MY opinion CODE goes hand in hand with safety since it all originates from the NFPA standards…

In your case here…you would not want to seperate the grounded conductors and equipment grounds because in this set up it is needed but would not fly in todays wiring methods for many reasons.

The reason their is a removal of the neutral to case bond at the sub-panel is to remove dangerous voltage from metal parts, ground faults SHALL BE removed by giving effective paths to equipment for an effective ground fault current path.

Putting potential neutral loads to grounded metal could result in electrified metal cases and so on for a lack of better explanation…been a long day so I am trying to be brief…

Load-side equipment to prevent fire, electric shock, elevated magnetic fields, or improper operation of sensitive equipment, equipment and circuit conductors shall be bonded in a manner that prevents objectionable neutral current from flowing on conductive material, electrical equipment, or on grounding and bonding paths. ( 250.6) This is accomplished by not having a neutral to case bond connection on the load side of the service equipment, except as permitted by 250.142(A)(1) through (3).

with that said…in my long winded way…it is not up to the current safety standards but again probably was at the time it was done so while I think you should call attention to it and most certainly is a potential safety hazzard…do it in a way it covers it but does not reflect something the client HAS to change but should think about changing…while you can suggest it…the NEC ( again in my opinion hand in hand with safety ) would say it can stay…but again not allowed in this manner today !

Also I am sure you mentioned about the open KO’s, the blackened neutral wires on the right side and the doorbell transformer in the panel as well.

Not to mention the panel probably has a rating of the number of OCPD’s allowed in it based on its age so the addition of tandam breakers may exceed the rating for the enclosure…has nothing to do with consumption…totally a rating of the allowed OCPD’s within the enclosure…

For example…many today say 30/40 panels…this means it will handle 30 FULL side breakers…but will allow 10 tandoms in specific locations within the panel to meet the 40 circuit rating of the panel…please dont confuse the two…just in case.

Also suggest they re-identify the white wires on the 2 pole breaker…

Also I do not see a GEC from the disconnect to a ground rod so I will assume a waterpipe ground only…was that sized correctly and in the correct fashion…distance to the entrance of the dwelling shut off and so on.

With all of that said :wink: you should still defer it to an electrician to verify that separation of grounds and neutrals is okay or not okay (I still say not). :smiley:

As HI’s, it’s best to try and not be the “expert.” When I see G’s & N’s bonded at load side panels, I defer it - period. Let the Sparkies sort it out as Abernathy did.

lol…man I hate that term…sparky…lol…it implies we like to see sparks…NOT…

Actually what i was saying is…in the PICTURE you would have to leave the neutrals and grounds together in the sub-panel…otherwise you will have issues since their is no 4th wire…

But you are correct jeff…it is a problem, should be pointed out and in all cases refered to an Electrician…theheheheheh

Notice I took out the HUMOR in the post…thehehe

You mean I cant just say it’s a bag of sh*t, and recommend an upgrade be performed?

Seriously, though… In this case, I probably would point out some defficiencies by today’s standards, and suggest an upgrade. Of course, I always call out for further evaluation by a licensed electrical contractor, who will likely also recommend an upgrade…