Checked against primary sources 2026-08-24

Temporary is a condition with an end date, not a lighter code

One figure in days appears in the Article 590 time constraints, 90, and it belongs to holiday decorative lighting. Everything else in the article is the ordinary code with a few named departures, plus protections the ordinary code never asks for.

The sentence the whole article hangs on

A temporary installation meets everything the code asks of a permanent one, except where Article 590 specifically says otherwise. That default sits near the front of the article, and every paragraph after it is either a named departure from the default or an addition to it.

Read that default in reverse and a whole family of items becomes unanswerable, because you go looking for permission the article never grants. A candidate who believes temporary means relaxed will take the answer choice describing something sloppy, and that choice is in the item because the belief is common.

The reflex that works: assume the ordinary rule applies, then check whether the article names the specific thing the question describes. Usually it has not.

The article also leaves the authority having jurisdiction a say. A temporary wiring method is acceptable when it is approved for the conditions of service and for whatever is special about that installation, which is why two inspectors can land on two answers about the same detail on two sites.

Three permitted uses, one number of days

Only the seasonal category carries a day count. The other two run as long as the work or the event lasts, and the article attaches no calendar to either.

• Construction, remodeling, maintenance, repair and demolition. Wiring for this work runs for the period of the work. No number of days attaches to it anywhere in the article.
• Holiday decorative lighting and similar purposes. This is the 90 days, and it is the only figure in days the time constraints contain.
• Emergencies, sharing one subsection with tests, experiments and developmental work. No period attaches to any of them, and an emergency is not handled separately from a test. Load testing a standby generator and a flood that took out the service sit in the same paragraph.

A fourth paragraph closes the time constraints, and it is not a permitted use at all. It is removal, and it gets its own section below.

So a day count in an Article 590 item is doing one job. It is checking whether you attach 90 days to the seasonal lighting where it belongs or to the construction site where it does not. The distractor takes the 90 days and hangs it on a job trailer, a spider box, or a temporary pole that has been up since spring.

What is genuinely relaxed

The relief runs to getting conductors from the panel to the work, not to how anything is protected.

Feeders and branch circuits get latitude in the wiring methods open to them. Cable assemblies are on the list, so are cord and cable of the hard usage and extra-hard usage types, and Type NM and Type NMC lose the height limit and the building-construction limit that bind them in permanent work, and they do not have to be concealed. The conditions attached usually turn on how high the conductors run, what can drive into them, and whether they are protected from damage.

A box is not required for every splice. Where the circuit conductors are multiconductor cord or cable assemblies on a construction site and the equipment grounding path stays continuous, the splice can go without one. Support is looser too, staples and ties and straps at whatever interval keeps the cable out of harm, rather than a fixed spacing off a table.

Vegetation stays off the list of things you can hang a span from, with one exception that belongs to the seasonal category. Holiday lighting can go up in a tree when it is rigged so that the tree moving does not damage the conductors.

That is not the whole list, and the point is the shape of it rather than the contents. None of it touches overcurrent protection and none of it touches grounding and bonding. Feeder protection still comes out of Article 240, receptacles still get a grounding terminal tied to an equipment grounding conductor, and nothing in the article lets a temporary circuit go ungrounded because the job is short.

What temporary work gets that permanent work does not

Ground-fault protection for personnel is the addition candidates meet first, and it is the most tested paragraph in the article.

Receptacle outlets in use by the people working on the site get ground-fault protection for personnel. Not because the receptacle is temporary, but because the site is wet, the tools take a beating, the cords get run over, and the grounding path on a job under construction is the least trustworthy one in the trade.

The feature that catches people is which receptacles it reaches. It is not limited to the ones installed as part of the temporary wiring. A receptacle belonging to the permanent installation that is being used for construction power falls under the same protection, and the article gives that case a paragraph of its own. Read the voltage and ampere ratings off your own copy rather than a remembered list, because that is where the wrong answer lives.

For the outlets the receptacle rule does not reach, the article names an alternative. A written program of testing equipment grounding conductors and receptacles, enforced on the site, run to a schedule, with records, stands in place of devices. The distinction an item wants here is that it is a program somebody runs, not a thing you screw into a box, and a candidate carrying a rule of thumb that Article 590 never relaxes protection will strike this answer out and lose the mark.

Ground-fault protection is not the only addition either, and treating it as the only one costs items. Lamps for general illumination get a guard against accidental contact and breakage. On a construction site the receptacles stay off the branch circuits feeding the temporary lighting, so one tool faulting does not put everybody in the dark. Each temporary circuit gets a disconnecting means for its ungrounded conductors, and a multiwire branch circuit gets a way to open all of them together.

The removal rule

Temporary wiring comes out immediately on completion of the construction, or of whatever purpose it went in for. Not at the convenience of the contractor, and not when somebody gets around to it.

That one sentence catches people in the field constantly. Temporary lighting that stayed up for the tenant. A spider box left on a column after the crew moved on. A temporary panel that quietly became the permanent panel for a shop bay because nobody wanted to pay to redo it.

On the exam it catches people differently. An item describes an installation that was compliant while the job was running, tells you the job finished, and asks about its status. The answer is not about how it was built. It is about the permission having expired.

This is the cleanest example of the point the whole article is making. Temporary describes a condition with a beginning and an end, not a quality of workmanship.

How the item is usually worded

Article 590 items tend to describe a site rather than a circuit, and the description is doing the work.

• A number of days. Ninety is the seasonal lighting allowance. Hung on anything else in the article, it is the wrong answer, and hung on construction work it is the wrong answer twice over because construction has no day count at all.
• A receptacle in use by workers. The question is ground-fault protection for personnel, and often whether the receptacle belonging to the permanent wiring changes the answer. It does not.
• A finished job with wiring still in place. The question is removal.
• A wiring method described loosely. The question is whether the article names it, and where it does not, the ordinary rule still stands.
• An emergency, or a test, or developmental work. The question is usually whether you think one of those has a clock on it. None of them does.

Every one of those is a two-minute lookup for somebody who has opened the article once and a coin flip for somebody who has not.

An hour, and where to put it

This article is short. That is the argument for reading it rather than skipping it.

1. Read Article 590 front to back in one sitting. It is one of the few articles in the book you can do that with.
2. Mark the sentence saying the rest of the code still applies. Most items are built against it.
3. Mark the time constraints and write 90 beside the seasonal paragraph only. Leave the construction paragraph and the emergency paragraph bare, because that blankness is the answer to a whole class of items.
4. Mark the ground-fault paragraph, note the voltage and ampere ratings your copy gives, and find the paragraph that covers receptacles belonging to the permanent wiring.
5. Mark the removal sentence. It is short and it is easy to walk past.

One thing to watch if you have just bought a new book. Find rules in this article by heading rather than by a section number you memorized, because at least one paragraph inside Article 590 sits at a different number in the 2026 edition than it did in 2023, and hunting for it by the old number on a timed exam is time you do not have.

Texas adopts the 2026 National Electrical Code effective 1 September 2026 under 16 TAC 73.100, and the examinations are referenced to that edition from the same day, so the ratings you check should be the ones in the 2026 book.

What this page cites

• NEC Article 590 Temporary installations. The time constraints and their three permitted uses, the departures from the general rules, ground-fault protection for personnel, the grounding conductor program, and removal. At least one paragraph inside the article carries a different section number in the 2026 edition than it did in 2023, so find rules by heading in your own copy.
• NEC 210.8 Ground-fault circuit-interrupter protection in the general chapters. This is the section whose voltage and ampere coverage has widened across recent editions, and it is written separately from the temporary-power rule. Do not carry ratings from one to the other.
• 16 TAC 73.100 Texas adoption of the 2026 National Electrical Code, effective 1 September 2026. source
• PSI Candidate Information Bulletin, TDLR Electricians Updated 9 July 2026. States that from 1 September 2026 the examinations are referenced to the 2026 NEC. source
• Electrical Contractor Magazine, on the Article 590 time constraints Jim Dollard on what each subsection covers: the construction period, the 90 days that belongs only to holiday decorative lighting, and the subsection that puts emergencies together with tests such as load testing a standby generator. source
• EC&M, The Basics of Temporary Installations Walks the article from the time constraints through removal, including lamp guards, splices without boxes, the support rules and the vegetation exception for holiday lighting. source