Heavy up is one of those peculiar, specialized terms in the world of home renovation and electrical systems. Essentially, heavy up means to increase the amperage coming into your house—at the service panel—so that your electrical system can receive and handle an increased load. The entire service panel usually will need to be replaced as part of the heavy up project.
Indications You Need a Heavy up
If your home was built within the last 20 to 30 years, it is unlikely that you will need a heavy up. Two-hundred amp service likely will be found in your home.
Yet older homes' electrical systems may not have the ability to match today's needs. Some items may not even have existed when your home was built: televisions, dishwashers, large HVAC systems, computers, and hot tubs. Since earlier electrical needs were so much smaller—lights, outlets, and a few small appliances—the systems were smaller, as well.
Common scenarios that may indicate the need for a heavy up in your home:
Lights may flicker when another electrical current draw is started. This is especially true when that second draw is a heavy one: a bathroom heater, an electric oven, or even a small appliance such as a blender that draws power quickly.
When circuit breakers shut off frequently, this can be an indication that your electrical demand is exceeding the limits of your home's system. Note that the circuit breaker might be faulty and need to be switched out. Arc-fault protection breakers often have false positives.
When you have an older style service panel with fuses instead of circuit breakers, that's usually a sign that you need to replace the service panel and heavy up in the process.
When you are undertaking a major remodel, this is always a good time to begin evaluating your electrical system.
When you are putting on an addition or doing anything else that will increase your home's square footage, you will have greater electrical demands. In some cases, you may need to install a sub-panel to serve the new space. A sub-panel does not give your home more electrical power. Instead, it's an intermediate waypoint that allows you to branch off more circuits and to keep those circuits better organized.
Air Conditioners or Shops
If you plan to add a service that is a major power draw, such as an air conditioner, you may need a heavy up. If you have a welding unit in a workshop, you will also need a heavy up.
Amperage Increases and Other Upgrades
A typical heavy-up is one in which an older house needs to be upgraded from 100 or 150 amp to 200 amp service, which is the standard now.
If your home has the old knob-and-tube electrical system, your entire electrical system may need replacing. Age can take its toll on knob-and-tube systems: the rubber on the wires becomes brittle and the knobs can break. Another disadvantage of knob-and-tube systems is that they are not grounded.
In theory, knob-and-tube is not inherently inferior to today's system of plastic-coated wires as long as your electrical needs remain within limits. At the same time, you should switch out knob-and-tube wiring whenever you get a chance, when you open up a wall or the ceiling.
Can You DIY a Heavy up?
Most do-it-yourselfers are not equipped to perform heavy up work by themselves. A heavy up is a major undertaking, requiring the services of a licensed electrician since it entails the replacement of the entire service panel and shut-down of the power coming into the house from the service drop.
Many communities will not even allow homeowners to add a new electrical service panel, instead requiring that only licensed electricians perform the work.
Estimates for heavy ups to 200 amp service range from $1,500 to $3,500. The majority of this estimate is devoted to labor. Materials are relatively inexpensive: 30-space service panels range from $100 to $200 and 20 amp circuit breakers range from $3 to $5 per breaker.
A grounding rod may need to be driven into the earth just outside your home and attached to the service panel. The cable that is used for the service drop (from the power line to your house) may also need to be replaced.
The electricians should also be able to apply for the permit, as well.