Tips for Identifying Size of SE Cable

[busman]

In my area, most of the service upgrades include new service entrance conductors, so I don't see a lot of this. Current situation is modern (plastic jacket) SE cable that is fully painted, so no markings are visible. On the hot conductors, the insulation goes right down to the lugs, so I can't even see it it's compact or regular stranding. Any tips on identifying the wire gauge? I'm sorry. I can't tell 2/0 from 1/0 just by looking at it. I'd have to measure.

I'd like to know the size of MCB panel I need without disconnecting the wires and cutting a cross section to measure.

Any ideas greatly appreciated.

Mark

 

[mcclary's electrical]

In my area, most of the service upgrades include new service entrance conductors, so I don't see a lot of this. Current situation is modern (plastic jacket) SE cable that is fully painted, so no markings are visible. On the hot conductors, the insulation goes right down to the lugs, so I can't even see it it's compact or regular stranding. Any tips on identifying the wire gauge? I'm sorry. I can't tell 2/0 from 1/0 just by looking at it. I'd have to measure.

I'd like to know the size of MCB panel I need without disconnecting the wires and cutting a cross section to measure.

Any ideas greatly appreciated.

Mark

IMO, the size of the panel you actually need has nothing to do with your current SE conductors, but rather a load calc.

 

[Dennis Alwon]

My guess, if we are talking aluminum, is that of T.310.15(B)(6) #2 alum = 100 amps, 2/0 alum= 150 amps and 4/0 = 200 amps. I guess if your area uses 125 amps then the prob. would be from 1/0 to 2/0. I would look at the main breaker.

I realize that the riser, mast, etc only need to be that of the calculated load but generally , in this area, it is the size of the service.

 

[wireguy8169]

I realize that the riser, mast, etc only need to be that of the calculated load but generally , in this area, it is the size of the service.

Yeah, unless spec'ed at 125A I either install 100A or 200A 4/0 AL SE cable. But to answer your question, you could take a few straps off and see if the back side can be read.

 

[busman]

My guess, if we are talking aluminum, is that of T.310.15(B)(6) #2 alum = 100 amps, 2/0 alum= 150 amps and 4/0 = 200 amps. I guess if your area uses 125 amps then the prob. would be from 1/0 to 2/0. I would look at the main breaker.

I realize that the riser, mast, etc only need to be that of the calculated load but generally , in this area, it is the size of the service.

Sorry. Should have mentioned that this is an old split-bus panel, so no main breaker. I haven't done a load calc, but since the residence has all gas appliances, I would think it would be below 125A.

Also, I agree that the service cables need to be size for the load calc, but by 230.90 (2005), they need to be protected at their ampacity. Hence my question about the MCB for existing SE cable.

Thanks,

Mark

 

[busman]

Yeah, unless spec'ed at 125A I either install 100A or 200A 4/0 AL SE cable. But to answer your question, you could take a few straps off and see if the back side can be read.

Sorry. It's an underground feed to the meter. About 12 inches of SE cable on the outside of the house and about 8 inches on the inside. Not much to look at.

Are there different number of strands on the neutral for different size cables. Really grasping at straws here.

Mark

 

[Dennis Alwon]

Mark, short of a wire gauge tool I am not sure what to tell you.

 

[busman]

Mark, short of a wire gauge tool I am not sure what to tell you.

Yeah, that's the answer I expected. I guess I'll just have to show up with a 125A and a 150A and measure the wire when I get it out of the lugs. BTW, where'd you get the wire gauge shown? It looks like it covers SEU cable. Never seen one like that.

Thanks,

Mark