Texas Electrician ExamTexas journeyman & master

Checked against primary sources 2026-08-24

Almost nobody is electrocuted in the water. They are paralyzed, and then they drown.

Article 555 is one of the few places in the book where the hazard is legible in the requirement. The sentence that costs marks, and worse, is which device carries the tighter trip setting.

On this page
  1. What is electric shock drowning?
  2. Why the usual answers do not work here
  3. Which ground-fault device carries the tighter setting?
  4. What does the leakage current measurement device have to do?
  5. What else is in Article 555?
  6. How many exam items is Article 555 actually worth?
  7. What this page cites

What is electric shock drowning?

It is drowning caused by current in the water immobilizing a swimmer who was otherwise fine. There are usually no burns, no marks, and nothing on the body to say electricity was involved.

The physics is unkind in a specific way. Fresh water is a worse conductor than a human being, so when leakage current is loose in a lake or a river, a swimmer arriving in that field becomes the easier path and current goes through the body in preference to the water around it. Salt water behaves the opposite way, which is why this is a lake and river problem far more than an ocean problem, and why it matters in Texas.

The current involved is small. Well below anything that would burn, and below what most people picture when they think about electrocution. It is enough to lock the muscles a swimmer needs in order to swim, and after that the water does the rest.

Nothing about that is visible from the dock. The boat looks normal, the pedestal looks normal, and the only sign is a person in the water who has stopped moving.

Why the usual answers do not work here

Every other place in the book, the fallback is that a fault will draw enough current to open an overcurrent device. Not here.

The leakage that kills at a marina is milliamperes. No breaker anywhere in the facility will ever see it, and no amount of correct conductor sizing changes that. Whatever protects a swimmer has to be a device that measures the difference between what goes out and what comes back, and it has to be set low.

The second complication is that a marina leaks a little all the time and always has. Wet boats, long submerged runs, aging shore cords and dozens of vessels sharing one grounded conductor add up to a background of small leakage that a personnel-grade device would trip on constantly. Set the protection at the level that protects a person and nothing stays energized. Set it where the facility runs and it is no longer protecting anyone.

Article 555 does not resolve that tension with one number. It resolves it by putting different numbers at different points, and the whole article makes sense once you know which number sits where.

Which ground-fault device carries the tighter setting?

The shore power receptacle does. NEC 555.35 puts individual ground-fault protection of equipment on the receptacles that supply shore power to boats, set to open at a trip current not exceeding 30 milliamperes.

The looser number is upstream. Feeder and branch-circuit conductors installed out on the docking facility get their own ground-fault protection of equipment under NEC 555.35, and that one opens at not more than 100 milliamperes. In the 2026 edition the same rule reaches piers as well as docking facilities.

Reverse those two and you have described a facility where the device watching a single boat is the slack one, while the tight setting sits upstream carrying the summed leakage of every vessel on the dock. That is the arrangement Article 555 exists to prevent, and it is the most expensive thing in this article to hold backwards.

The reason for the split is arithmetic, not caution. A shore power receptacle sees one boat, so the background leakage under it is one boat's worth and a tight setting stays put. The feeder sees everything under it at once, and forty wet boats add up, so a 30 milliampere setting up there would leave the dock dark by Saturday lunchtime.

The third level, and the one people mix up

There is a level tighter than either of those. Receptacles at a marina that are not shore power, the ordinary ones somebody plugs a vacuum or a grinder into, take personnel-grade ground-fault circuit interrupter protection under NEC 555.35, which is a Class A device operating in the 4 to 6 milliampere band.

So two of the three levels are protection of equipment and one is protection of personnel, and they are not interchangeable. An item that hands you a marina receptacle and an answer choice in the single milliamperes is testing whether you noticed the words shore power in the stem.

A way to place a value you already know

Count what sits downstream of the device. The fewer things a ground-fault device has under it, the tighter Article 555 lets it be set.

That ordering holds for every ground-fault requirement in the article, which is why it is safe to lean on. What it will not do is invent a value you never learned. It sorts three numbers you already have into the right slots, and it is worthless if you have not read all three off the section first. Read them out of your own book and write each one next to the point it applies to.

What does the leakage current measurement device have to do?

Protection that trips tells you something is wrong. It does not tell you which of forty boats is wrong, and until you know that, the dock stays dark.

So NEC 555.35 calls for a leakage current measurement device, listed for use in marina applications, wherever more than three receptacles supply shore power to boats. It has to be available on site and it has to be used to determine the leakage current from each boat that will take shore power.

The qualifiers in that sentence are where the exam items live, and each one of them narrows the rule.

That last one is worth sitting with, because it inverts the obvious story. The device earns its keep before the boat is plugged in, not after something trips.

The trigger in the text is the boat, not the calendar. Nothing there sets a testing interval, so an answer choice offering you a frequency is offering you something the section does not say.

What else is in Article 555?

The signage section prescribes the words. An owner does not get to write the sign, and that alone is an item.

Three thirties, three units

Article 555 uses the number thirty for three unrelated things, and an item writer only has to leave the unit out of the answer choices to make that expensive. 30 milliamperes is the trip setting at the shore power receptacle. 30 amperes is the smallest shore power receptacle the article recognizes. 30 inches is the furthest a disconnect can sit from the receptacle it controls. Read the unit in the stem before you read the number.

One more thing arrived in the 2026 edition. The ground-fault protection at a marina now has to be coordinated and performance tested by qualified persons following the manufacturer's instructions, with a written record kept available for the inspector. It is a commissioning requirement rather than an installation one, which makes it the sort of new material that shows up as a knowledge item long before anyone sees it in the field.

None of that is hard. It is unfamiliar, which is a different problem and a cheaper one to fix.

How many exam items is Article 555 actually worth?

Nine, at the outside, and not all nine will be marinas. Special Occupancies, Equipment, and Conditions carries 6 of the 56 scored items on the journeyman knowledge portion and 3 of the 24 scored on calculations, and Article 555 shares that pool with hazardous locations, health care, agricultural buildings and the rest of the special occupancy and special equipment material.

The reason to spend the hour anyway is not that marinas are likely to be your work. The knowledge portion is scored on 56 items against a 70 percent cut, and in FY2025 fewer than one candidate in four cleared it, so nothing on that paper is a spare item. Texas has a great deal of fresh water with docks on it, and the effort per item here is lower than almost anywhere else on the paper, because the article is short and the same idea comes back three or four times.

  1. Read the scope at the front of Article 555, then read the definitions that matter in Article 100, where the current editions keep them. Docking facility and electrical datum plane both decide what the rest of the article means.
  2. Find 555.35 and mark all three ground-fault levels. Write the value and the point it applies to beside each one. The receptacle carries the tight number.
  3. Read the leakage current measurement paragraph to the period and mark the three qualifiers in it.
  4. Skim signage, bonding, receptacles and the disconnect once. You need recognition, not recall.

Sitting on or after 1 September 2026 means the 2026 edition, because Texas adopts it that day under 16 TAC 73.100 and the examinations follow.

What this page cites

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