Service Upgrade With Subpanel

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boboelectric

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Eighty Four,Pa.15330
A main entrance service upgrade I bid on (service only) feeds subpanel in basement fed by old style SE cable which was acceptable at time.Does code allow me to just land feeder on new breaker just as i would an existing range or dryer?
BOB O.84,PA.
 
Re: Service Upgrade With Subpanel

From my experiences with this issue, as well as the same with SE and the appliances you mentioned, hrer's what I understand to be the case:

It depends on the inspector.


In one case, we added an ATS and generator, which rendered the main panel a sub-panel, because of the new disconnect between the meter and ATS.

Most of the work was obvious: remove the EGC's and the enclosure bonding screw/strap from the neutral bus, and add a new EGC bus to the panel.

The pathway between the panel in the garage and the house was impassable, because what was a breezeway was converted into a habitable space.

What to do with the SE-fed major appliances? Tape the entire exposed part of the bare conductor with white tape and keep them on the neutral bus.

The reasoning was that this is a case of the neutral being used as the EGC, and not the EGC being used as a neutral; it carries current.


The other case was a meter relocation for an addition, with a disconnect added at the meter, and replacing the SE service cable with SER.

This time, I had to replace the appliance SE's with SER also, and change the receptacles and power cords, and even open up the appliances.

Sometimes you really have to disect a wiring harness to find the neutral/EGC interconnection, but at least it's a meeting of green and white.
 
Re: Service Upgrade With Subpanel

Originally posted by boboelectric:
A main entrance service upgrade I bid on (service only) feeds subpanel in basement fed by old style SE cable which was acceptable at time.Does code allow me to just land feeder on new breaker just as i would an existing range or dryer?
BOB O.84,PA.
Click to expand...
Huston we have a problem.

Although some inspectors will allow the original SE cable to remain for a service upgrade to feed the original panel when a new main is being installed it can pose a problem for the three wire range and dryer.

It is always best to change the three wire SE to a four wire SER to supply the original panel. Should the range or dryer of the original panel be on a three wire SE cable it MUST land in the new service main that you are installing.

250.142 Use of Grounded Circuit Conductor for Grounding Equipment.
(B) Load-Side Equipment.
Exception No. 1: The frames of ranges, wall-mounted ovens, counter-mounted cooking units, and clothes dryers under the conditions permitted for existing installations by 250.140 shall be permitted to be grounded by a grounded circuit conductor.

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 grounded 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 grounded 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 service-entrance 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.
Click to expand...
:)
 
Re: Service Upgrade With Subpanel

This can become a more complicated issue, therefore I for one say keep it simple. If a subpanel was installed improperly to start with, you are not doing anyone a favor by not correcting the situation. Simply put, correct the situation.

More complication comes from those who say... I will lose the job if I do this...so what. It will cost the customer more than they can afford...can they afford the potential of a house fire?

What if the panel supplies AC cables and the neutral/ground connection of the three wire was isolated at the subpanel...no equipment grounds for any of the AC circuits, yeah that is always a good thing. Like I mentioned, correct it, or walk away from it.... pretty simple.

Remember, relying on passing an inspection does not always make for the correct installation.
 
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