Larger wires at service drop

I never noticed this before. The wires from the pole look very small. Then at the mast they are bigger.

Could you please fill in the blanks for me with whats wrong here or what could happen vs the main breaker size?

One is copper and one Alu?

Same rating?

Appears that even the stranded Al wire changes sizes at the clamp. Interesting question and I wish I had an answer for you but APS or SRP own the incoming lines and maybe a call to them would help. Or one of the electrical folk on this site can shed some info on the setup.

This is quite typical as the utilities do not use the NEC tables to size their wires.

The conductors have different insulation ratings and can radiate heat better by being in free air.

It is quite common for the overheads not even to be upgraded when a service increase is done.

Good answer Jim!! I actually new what you saying. (Electrical has been one of my weaker areas)

I have a question pertaining to the clamp on the stranded wire. Is this an acceptable method of attaching the 2 wires? Shouldn’t a similar clamp be used like the other two wires?

They are both Al wires.

The other two wires DO have the same H tap, you just can’t see them because they are covered. The neutral does not need to be covered. It is a POCO connection, they are all done like that here (Tucson Electric Power).

One strand inside the neutral is a steel wire. This provides the support for the triplexed cable. The clamp on the stranded wire has the steel passing thru and going to the eyebolt on the mast.

The insulated conductors do not need a clamp as the triplex construction is all supported off of the carrier strand. The cable acts as a unit.

The way he said “attaching the 2 wires” I think he is referring to the H tap.

Yes, it is not necessary to put an HTap cover on the neutral. The neutral conductor is bare to begin with, so putting a cover on the HTap of the neutral is pointless and wasteful. The HTap’s themselves cost about 85 or 90 cents, but the covers are 4 to 5 dollars each.

Yes, but I am wondering about the smaller wire size coming from the pole then jumping up to a larger size into the meter and panel.

Happy New Year Mark.

Jim answered your wondering in post #4:

Well then, quit worrying so much. :mrgreen:

It’s completely normal. The power companies size their conductors to NESC rules, and electricians size their wires to NEC rules. Two different animals. Unless the customer is having problems that can be attributed to voltage drop (lights dim severely when you turn on the disposal, etc.), it’s not even worth a comment.

Marc, I am not an electrician so bare with me.

My mother in laws house got upgraded from a 100amp to a 200 amp. The wires coming from the pole were 100amp wires and the power company changed them to a 200 - 300 amp size. Then those same size wires were brought down into the panel and a 200amp breaker was installed so the panel is a 200amp panel.

The wires in the note above look very small like 60 - 100amps. Are you saying its ok to put larger feed wires to the panel to upsize to 200amps?

As mentioned by Jim earlier in the thread, the size of the conductors from the pole to the weatherhead are sized based on the Utility codes - NESC. The size of the conductors from the overhead splice (service point - which is the load side of the utility conductors - service drop), are sized on the NEC.

The utility company will size their conductors based on the past usuage. So, if there is a service change, from 100A to 200A without a load change, the utility company will not even change their conductors from the pole.

The Utility company will size their conductors based on usuage (utility bills) and any additional calculated load(s). This conductor size will still be smaller than the NEC requirement.

Wow this is interesting info! How does the power company know that if the conductors were feeding a 60 amp breaker/service that when they switch the panel to a 300 amp service the wires wont burn up?

I wonder how come in this area they always switch the conductors when they go to a 200 service?

Yes you are right about that, when you upgrade to 200 amps going thru the proper channels TEP always brings in a new triplex. That one in the pic looks like what they use for 100 amps. Was there a 200 amp service? It is possible the POCO was not involved, some of us do have the ability to install H taps.

If you want to check on it just call Development Services, ask for the permit counter and ask for a permit history on the address. Anyone can do it and it’s free. Keep in mind the City of Tucson and Pima County are in different offices. See if there was a permit for an upgrade, and most importantly, if it was finalized.

They have your power bill as history. Every area does it differently. A service upgrade doesn’t necessarily trigger a change of the aerial drop.

The vast majority of upgrades done here are for increased capacity such as for the addition of air conditioning unit(s) or additions to the structure, which would also require additional cooling. A 5 ton AC unit would certainly increase the load, no?

I find it hard to believe that a POCO would actually review past usage to determine if a bigger drop is needed.

I work with the local POCO where the Mark’s client is located and I can say without a doubt that if there is a 200 amp main under that mast then something went wrong, a bigger triplex should have been brought in.

This is the split buss panel.