"Heavy up" is one of those peculiar, specialized terms in the world of home renovation and electrical systems. Essentially, it 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.
If your home was built within the last 20 to 30 years, it is unlikely that you will need a heavy up. 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:
- Lights flicker when another electrical current draw is started (such as a heater or bathroom fan turned on).
- Circuit breakers shut off frequently.
- You have an older style service panel with fuses instead of circuit breakers.
- You are undertaking a major remodel.
- You are putting in an addition or doing anything else that will increase your home's square footage.
- You plan to add a service that is a major power draw, such as an air conditioner.
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. Knob-and-tube is not inherently inferior to today's system of plastic-coated wires. 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.
This is not the job to do yourself, in general. A heavy up is a major undertaking, requiring the services of a licensed electrician since it entails replacement of the entire service panel and shut-down of the power coming into the house from the service drop.
Estimates for heavy ups to 200 amp service range from $1,300 to $3,000. 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.