Figures in an article yesterday about business capital spending plans for 1986, which were attributed to the Commerce Department, were instead a Wharton Econometric Forecasting Associates projection of what the latest Commerce survey, whose results are being tabulated, will show.

U.S. firms, expecting a tough year with little growth in sales, currently plan to reduce capital spending in 1986 by 1 percent, according to a survey by McGraw-Hill Economics released yesterday.

If capital-goods prices increase as much as companies expect, however, the decline in real spending for new plants and equipment will be more than 5 percent.

With many forecasters expecting gains in consumer spending to slow next year, a decline in real business investment in new plants and equipment could mean continued slow overall economic growth next year, analysts said.

The forecast was only the fourth in the 32-year history of the McGraw-Hill survey to predict a decline. The three previous instances came during recessions, and each proved to be accurate.

The poll, taken in September and October, drew responses from 540 major companies that account for about 30 percent of capital spending in the United States.

The companies said they expect to trim capital outlays to $380.7 billion in 1986, a 1 percent decline from the estimated 1985 level of $384.4 billion. With inflation in capital-goods prices taken into account, they plan to cut real investment by more than 5 percent -- though McGraw-Hill cautioned that firms usually overestimate how fast capital-goods prices will rise.

Factories, mines and utilities are operating at only 80 percent of their production capacity, according to the Federal Reserve, and businesses are reluctant to invest to increase that capacity. Other surveys this year have shown a fairly steady trend of cutting back investment plans.

A recent poll by Rinfret & Associates, a New York economic consulting firm, also showed a drop in capital spending for next year. The latest Commerce Department quarterly survey of investment intentions showed only a small 0.5 percent increase for all industries in 1986.

Even in the Commerce survey, the total for manufacturing was expected to drop by 0.5 percent in real terms, while the non-manufacturing total was up 1.4 percent largely because of added investment by utilities and communications industries.

However, the McGraw-Hill survey found that non-manufacturing firms are planning to reduce their investment spending by 1.7 percent before adjustment for inflation, while manufacturers are planning to increase theirs by a tiny 0.2 percent. But after adjustment for inflation, both sectors will be spending less than in 1985.

The deepest cuts, 19.3 percent and 15.5 percent, are projected by mining and by energy producers and distributors, respectively.

Makers of durable goods plan to cut their investment outlays by 2.1 percent. The stone, clay and glass industries project a 9.6 percent spending drop, and autos, trucks and parts, a cut of 6.3 percent.