GrandPappi

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wyreman

wyreman

Senior Member
Location
SF CA USA
Occupation
electrical contractor
So I have an 1959 apt building each init has electric cooktop and little oven. I calculate 56 amp per unit. The feed is old 3 wire #8 w ocPd at 50a FP. So if I replace the disco and the loadcenter, I have to present a case to AHJ to allow this to run at 50A even tho I calculate 56. Any ideas of how I should frame my position if it comes up, grandpappi?0A7D288F-5270-4F2A-9D88-12984809A150.jpg8BADA0C0-4049-4C3C-9DFB-A7C2D7971BAE.jpg
 
Afci/ Gfi combo cbs

Afci/ Gfi combo cbs

It’s an old 3 wire cable #8
It’s been fine for 60 years.
Is there any way that could’ve ever been compliant back then?
Ampacity hasn’t changed , maybe the calcs?
There’s nothing there- 800ft^2, a hood vent, 10kw of cooking. That’s it

The whole point of the work is to replace the Fp panel
Worst case they Would have nuisance tripping on the new disco

It would take a lot of disruption to pull new wire
Opening walls and ceilings
Plan to install combo Afci Gfi cbs so I can replace all the 2 wire outlets w 3 prong
 
I am thinking the load can be worked with to get it under, one way or the other. It may be possible to work with a meter and run everything and then get an idea of what would have to be disabled to get under. Worst case the cooktop could come out entirely for a different appliance.

The 3 wire vs 4 wire is an issue ... Are you saying you have a cable with two hots, neutral, no EGC. There is no way I would put three prong outlets and GFI on that. And definitely not for a needed update. Repair or update. If you do not have an EGC in the feeder cable and you are changing the panel, I would probably be looking to change the feeder to SER.
 
__dan said:
The 3 wire vs 4 wire is an issue ... Are you saying you have a cable with two hots, neutral, no EGC. There is no way I would put three prong outlets and GFI on that. And definitely not for a needed update. Repair or update. If you do not have an EGC in the feeder cable and you are changing the panel, I would probably be looking to change the feeder to SER.
Click to expand...

I’m going over there now I’ll look to see if there is a ground in the feeder, the last time I looked in there briefly I was more interested to see if it was number six or number eight.
I only started to think about the grounding when I saw all the 2prongs were two prong but by then the cover was back on the Sp
 
wyreman said:
It’s an unground subpanel w 3 wire feed
Shoot!
Click to expand...

How about
NEC 300.3(B)2
　

(2) Grounding and Bonding Conductors. Equipment grounding conductors shall be permitted to be installed outside a raceway or cable assembly where in accordance with the provisions of 250.130(C) for certain existing installations or in accordance with 250.134(B),

250.130(C) Is for branch circuits

250.134(B) sane raceway or cable
https://www.electriciantalk.com/f2/no-equipment-ground-sub-panel-271456/index2/?amp=1&utm_source=amp
The branch circuits don’t have egc either so
I better wait to talk to ahjCC745960-112F-4195-ABEB-3657B38EF9BB.jpgCC745960-112F-4195-ABEB-3657B38EF9BB.jpgF64D9AA0-DB1F-4608-B3BC-9939E58273EF.jpg
 
Since it’s too small, and no ground
I’ll have to recommend replacing the subfeed w #6 or #4
 
wyreman said:
Since it’s too small, and no ground
I’ll have to recommend replacing the subfeed w #6 or #4
Click to expand...

Oh it’s actually a number six! And
None of the loads have a ground wire in them
so what’s the point in re-pulling the subfeed?
 
The only point is to ground the box itself kind of like a dryer.
Well grandpappy, do we have to pull a new wire?
There is no way to bootleg the neutral

I think the last time you were allowed to grab the cold water pipe
was sometime in the late 70s or early 80s, So
That is a question of the grandfather having jurisdiction
Knowing this jurisdiction,
I have a feeling he’s going to say pull a new wire
because, there’s no cost to him!
I’ll let you know on Monday thanks guys
Have a great weekend!
 
Oh this thread should been in the code question section
in the engineering section, maybe that’s why there’s no replies.

Ts evening I’ll summarize this thread and move it to the NEC
Section regarding the grandfather thanks again guys
 
Rubba wrapper

Rubba wrapper

#6/3 no ecg. Cloth wrap
 
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wyreman said:
Nope, it’s a 6/3 no ground
Click to expand...
Then, in my opinion, the only options are, in no particular order:

Leave everything as it is; leave 2-wire receptacles

Use the neutral as an EGC

Add an EGC

Replace with a cable with EGC



Realistic choices: leave everything as is (as are?) or replace feeders
 
wyreman said:
It’s an old 3 wire cable #8
It’s been fine for 60 years.
Is there any way that could’ve ever been compliant back then?
Ampacity hasn’t changed , maybe the calcs?
There’s nothing there- 800ft^2, a hood vent, 10kw of cooking. That’s it

The whole point of the work is to replace the Fp panel
Worst case they Would have nuisance tripping on the new disco

It would take a lot of disruption to pull new wire
Opening walls and ceilings
Plan to install combo Afci Gfi cbs so I can replace all the 2 wire outlets w 3 prong
Click to expand...

I'm not understanding. Since when does replacing a panel necessitate replacing the feeder as well? :? Change the panel and call it a day.
 
LarryFine said:
Then, in my opinion, the only options are, in no particular order:

Leave everything as it is; leave 2-wire receptacles

Use the neutral as an EGC

Add an EGC

Replace with a cable with EGC



Realistic choices: leave everything as is (as are?) or replace feeders
Click to expand...

Leave everything as is means don't replace the FP panel?

to replace the FP we need to run new cable?

And then... the loads don't have any ground so...
GFI is not an option to replace two prong recpts on a two wire ct?

I believe you have to replace the afci circuit breakers with afci cbs anyway...
 
peter d said:
I'm not understanding. Since when does replacing a panel necessitate replacing the feeder as well? :? Change the panel and call it a day.
Click to expand...
ok here is california lets see what the building dept says tomrw morning what i will need to do...
just looking for what the boys have to say aboutit
 
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