100 Amp Service Concerns

[taf]

I was changing out some ceiling fans at a family Summer cottage in Sullivan County, NY last Fall. When I went to turn off the main breaker on the Square D QO panel so I could change the fan, I noticed that there was no main breaker, but rather the incoming service cable went to a Square D 70 amp QO breaker in the main lugs. This seemed odd, but I proceeded with my task. When I finished, I called my aunt to inquire about the electrical service, since she had contracted to have it upgraded in 2007 for ~$800.00 in order to handle the installation of an electric range/oven (to replace a propane-fueled oven).

She informed me that she had the service upgraded to 100 amps and had the receipt for the work and the "Final Inspection" certificate and obviously I don't know what I'm talking about. I called the electrical contractor and he stated that the service was upgraded to 100 amps but that there was no 100 amp breaker there so he installed the 70 amp breaker.

This past week, when I was bringing some items up and turned on the electrical power, it still just bugged me because there is a 60 amp breaker on the range and a 30 amp breaker on the clothes dryer and a 40 amp breaker on the electric water heater. Not to mention there are 4 bedrooms, 8 ceiling fans and other lights and receptacles on the system.

I went out to check the service entrance cable and found AWG 4 Alumaflex cable. Now, this is not AWG 4/0 but rather AWG 4, approx. 3/4" - 7/8" wide NM AL cable. Allegedly, the contracor upgraded the service to 100 amps and installed a new meter-pan. However, it doesn't seem to me that AWG4 aluminum cable can handle 100 amps, since it is only rated for 65-75 amps, depending on what the operating environmment temperature is.

Here are my questions:

1.) Is AWG 4 SE Aluminum cable used for 100 amp service?
2.) Doesn't this scenario confirm that the actual service capability is only 70 amps?, and
3.) Doesn't the installation of the 70 amp breaker limit the available service (even if it was 100 amps) to 70 amps available for branch circuit feeds?
4.) How do I determine the rating of the main lug panel installed to see if the buses can handle 100 amps (I'm a little suspicious at this point)? Also, where might I find the model and rating info for the main lugs?)
5.) Is there a safety problem, (epecially regarding overcurrent protection) with using a main lug panel as a main service panel?

[HayZee518]

Service Entrance

For a 100 amp entrance 4/3 copper or 2/3 aluminum should be used. Since you mentioned 4/3 as installed by the contractor, he did not upgrade to 100 amp like your relative said. The 70 amp he installed is ok for the wire size he put in.
Now for the next part of your question, a main lug panel can be used as a service entrance panel as long as the main is back fed from the wires coming from the meter trough. If the wires go to the main lugs then there is no protection against overload. You are then depending on the line side fuses for the step down transformer at the pole. This transformer is rated at 4.8Kv with amperage draws in the Milliamp range. If this is where the wires are, then whomever inspected it ought to be shot, tarred and feathered and run out of dodge! THIS IS A DEFINITE NO-NO!