Question of the Day

Not quite. The answer is A: True

The de minimis exception applies to small appliances the same way it applies to any other regulated equipment — it covers the trivial, effectively unavoidable release that happens when hoses and gauges are connected or disconnected during normal service, as distinct from deliberately venting a system's charge to avoid recovery.

Not quite. The answer is B: An opening in a wall or parapet that allows water to drain off a roof as overflow, without a piped connection to the storm drainage system

A scupper is a through-wall opening that lets ponding water spill off the roof edge once it rises above the scupper's sill; because nothing is piped to it, it can't clog the way a strainer or a piped drain can. The UPC accepts scuppers or an open-sided roof as secondary drainage where the roof perimeter extends above the roof and traps water, with openings at least 4 inches high.

Not quite. The answer is D: When the primary overcurrent device is rated no more than the percentage of primary current allowed by Table 450.3(B) — 125% where the primary current is 9 A or more

For transformers rated 1,000 V or less, Table 450.3(B) permits protection on the primary side alone if the primary overcurrent device is rated no higher than 125% of primary current when that current is 9 A or more (higher percentages apply at lower primary currents, with next-higher standard size allowed where 125% is not a standard rating). Otherwise, protection is needed on the secondary as well. Supervised-installation percentages belong to the over-1,000 V table, not this one.