Velect, Trumpy's absolutely correct. You need a lot more information to answer that question. Exactly what is the problem that is prompting this question? Have you contacted the serving electric utility? I am assuming these are electric utility wires and the NESC covers the installation.
You actually need the location in the span, the length of the span, the attachment heights at both poles, the low point of the sag, and the temperature when measured just to calculate the blowout and maximum sag under hot weather loading or winter ice (whichever is worse).
If the wires are actually over the house, all the same information is needed as well as the height of the roof where the wires pass over, the type of roof so to ascertain whether it is accessible by pedestrians (by the NESC rules, forget the definition of accessible in the NEC for this application).
Trumpy did a good job of answering your question but you really need the services of the serving electric utility's trained engineer who is familiar with the NESC or his company's standards since they are based on the NESC and will either meet or exceed the Code.
- - - - - - - - - - - - - - - - - - - - - - - - - - -
Charlie Eldridge, Indianapolis, Utility Power Guy