how much does it cost to update the electrical systems in an old house?

Question

it is for an old 1928 house, and it has a 50 amp box

Answer 1

There is no way to estimate this without having someone look at it. It won't be cheap to have it done for a couple of reasons. 1: Wires should all be replaced . 1928 insulation is probably cotton impregnated with rubber and is probably falling apart. 2: outlets are probably 2 prong, no ground and should be replaced. 3: 50 amp box needs replaced, with today's electric appliance and all of our other goodies 150-250 amp is more reasonable.
You could pull the wire ( Romex ) yourself and replace the outlets. The box will depend on if the service to the house has to be increased. This will require your electric company to run new wire to the house.

Answer 2

The reason it is impossible to estimate this way is that so much depends upon the structure itself - its size, construction and layout. A unit cost of $65 - $95 per wiring device location plus additions for equipment and branch circuit runs isn't out of line. Bear in mind that the skill of the contractor you use can also bear on total costs. Some electrical contractors are not prepared to wire existing structures without creating considerable surface damage, which can add other repair costs and inconveniences to the job. Some ECs specialize in rewiring older, historic homes, and are sensitive to the finishes. If your 1880 has intact trims, crown mouldings, and original wood flooring that you would like to preserve (as I hope you would), you would do best to find an old house specialist. Such a contractor myself, I take pride in leaving only new wiring in a renovated home - not damage left to the homeowner to repair. Our company's per unit cost for wiring may be higher than our peers', but our client's overall job costs are lower. You could ask the local historical commission, architects' society and neighbors for help in locating a historic renovation EC in your area.