Short answer: order a freestanding outdoor cabinet whose interior is at least 2 in [50 mm] wider, 4 in [100 mm] deeper and 2 in [50 mm] taller than the relay panel, bolt it to a raised concrete pad, and lock the gasketed door. For a 50 x 20 x 8 in relay cabinet that is a 60 x 36 x 16 in box in 304 stainless, or 316L where salt spray reaches the pad. Send the bottom conduit cutouts with the drawing so they arrive factory-cut and the rating survives the stub-ups.
Size the cabinet around the relay panel
Add the clearances first, then read the catalog. One inch of extra width per side leaves room for wiring and the removable backplate. Two inches behind the panel take the standoffs and stub-up bends. Two inches in front keep the panel's components clear of the door gasket. Two inches of height spare the top and bottom entries. The rule: interior at least 2 in [50 mm] wider, 4 in [100 mm] deeper and 2 in [50 mm] taller than the panel you are housing.
Run it for a 50 x 20 x 8 in (1270 x 508 x 203 mm) surface-mount relay cabinet:
- Width: 20 + 2 = 22 in [559 mm] minimum inside
- Height: 50 + 2 = 52 in [1321 mm] minimum inside
- Depth: 8 + 4 = 12 in [305 mm] minimum inside
| Catalog box (H x W x D) | Interior, from the CAD | Verdict for a 50 x 20 x 8 in panel |
|---|---|---|
| 48 x 36 x 16 in | 47.84 x 35.84 x 15.84 in | Fails: 47.84 - 52 = -4.16 in of height |
| 60 x 36 x 12 in | 59.84 x 35.84 x 11.84 in | Fails: 11.84 - 12 = -0.16 in of depth |
| 60 x 36 x 16 in | 59.84 x 35.84 x 15.84 in | Passes: 7.84 in spare height, 13.84 in spare width, 3.84 in spare depth |
The 48 x 36 x 16 in 304 box looks close and misses by 4.16 in. The 12 in deep 60 x 36 in box misses depth by a hair. The two that clear the panel are the 60 x 36 x 16 in 304 stainless enclosure and its 316L twin. A smaller 30 x 20 x 8 in panel needs 32 x 22 x 12 in inside, which a 36 x 24 x 16 in box (inside 35.84 x 23.84 x 15.84 in) clears on all three axes.
Heat is the smaller problem here. A dozen interposing relays and a 24 VDC supply add tens of watts, and that big stainless shell — about 4.8 m² of surface at 3.7 W/m²K — rises only about 3 K over a 50 W load, so no fans. Sun on the door adds more than the relays do; the outdoor heat-gain walkthrough shows how to count it. If the panel carries its own 120 VAC supply, the small-box power supply article gives the watt math. When picking a size is your next step, the enclosure selector narrows catalog boxes by inside height, width and depth.
Which NEMA type the pad needs
NEMA 250 draws the lines this way. Type 3R keeps rain, sleet and snow off the equipment, which suits a pad that never sees a hose. Type 4 adds hose-directed water and splashing from any direction, and that is what irrigation overspray and rinse-down are. Type 4X is Type 4 plus corrosion resistance: NEMA 250 gives the X another 200 hours of salt spray beside an AISI 304 test specimen (its Table 5-1D).
In US installations, NEC 110.28 keeps the two systems separate: an IP code alone cannot stand in for the enclosure type number, so a drawing that says Type 4X gets the type on the order, not only IP66.
| What reaches the pad | Type to order | Source |
|---|---|---|
| Rain, sleet, snow; no overspray, no hose wash | Type 3R | custom build |
| Sprinkler overspray, mud rinse-down, occasional hose wash | Type 4X in 304 stainless | catalog or custom |
| Salt air, de-icing spray, fertilizer dust | Type 4X in 316L | catalog or custom |
The full type list and its tests sit in the NEMA enclosure types guide.
304 or 316L at the pad
304 stainless serves most inland parks and fields. Chlorides change the answer: 304 pits under salt deposits and inside gasket crevices even at room temperature, and near 60 C (140 F) both 304 and 316L reach the chloride stress-corrosion threshold — a stainless door in full summer sun gets there. Within a few miles of salt water, or wherever plow spray and fertilizer land on the pad, order 316L; its molybdenum buys pitting and crevice resistance. Inland and dry, 304. Salt within reach, 316L.
Pad height, handles and bottom entry
Pour the pad so the cabinet floor sits 4 in [100 mm] above finished grade. That keeps the gasket line above snow melt, irrigation splash and mower contact, and lifts the stub-ups out of the mud. Bolt the cabinet to a welded or slotted-angle pedestal anchored into the pad; the free-standing panelboard article works the pad and mounting-height details, and the floor-bolting walkthrough covers the anchors.
Two code numbers set the heights. NEC 240.24(A) caps the center of the highest operating handle at 2.0 m (6 ft 7 in) above grade. A 60 in cabinet on that pad tops out at 64 in (5 ft 4 in), so a single-door box clears the limit with 15 in to spare. NEC 110.26(A) asks for 3 ft (900 mm) of clear working depth in front for 0-150 V to ground in Condition 1, plus at least 30 in of width. Keep the door free to swing 90 degrees and set the pad back from the fence.
Bonding and entry finish the job. A ground rod driven at the pad is an auxiliary electrode under NEC 250.54: bond it to the equipment grounding conductor, size that conductor from the feeder overcurrent device using NEC Table 250.122, and let the EGC carry the fault current while the rod assists. Send the bottom conduit cutouts on the drawing so they arrive factory-cut and the stub-ups rise straight out of the pad; the bottom-entry article lays out the details, and the after-you-cut article shows what a field hole does to the rating.
What to put on the order
| Order line | Spec for a 50 x 20 x 8 in relay panel | Why |
|---|---|---|
| Cabinet | 60 x 36 x 16 in (H x W x D); interior 59.84 x 35.84 x 15.84 in | clears the panel by 13.84 in width, 7.84 in height, 3.84 in depth |
| Material | 304 stainless inland; 316L within reach of salt | chlorides pit 304 even at room temperature |
| Rating | Manufacturer-rated NEMA 4X / IP66; not UL listed | overspray, hose wash, corrosion |
| Cutouts | Bottom conduit entries, factory-cut | stub-ups from the pad, rating intact |
| Mounting | Pedestal bolted to the 4 in concrete pad, floor at pad height | 64 in top stays under the 2.0 m handle limit |
| Door | Gasketed door with a lockable latch | the locked, floor-standing install |
One shorter path deserves a line: when the relay panel's own cabinet already carries an outdoor rating, bolting it straight to the pedestal uses fewer parts. The outer cabinet wins when you want one lockable door, one gasket line and hidden stub-ups, or when the relay panel is indoor-only and needs the Type 4X shell around it.
So the decision reads like this. Inland turf field: the 60 x 36 x 16 in box in 304 stainless, Type 4X, pedestal on the pad, factory bottom cutouts. Salt at the site: the same box in 316L. Rain-only exposure on a tight budget: a custom Type 3R cabinet of the same size. Build either one around the relay panel with 2 in of width, 4 in of depth and 2 in of height to spare, and send the drawing through the custom enclosure builder.
Enclosures in this article
| Enclosure | Material | Outside H x W x D / display | Rating |
|---|---|---|---|
| 60 × 36 × 16 in | 304 stainless | 60 x 36 x 16 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
| 60 × 36 × 16 in | 316L stainless | 60 x 36 x 16 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
| 48 × 36 × 16 in | 304 stainless | 48 x 36 x 16 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
Questions
Can the relay panel bolt straight to the pedestal without an outer cabinet?
Yes, when its own cabinet is manufacturer-rated for outdoor use and its mounting points take the load. A 50 x 20 x 8 in surface-mount cabinet on a raised pad works that way with the fewest parts. The outer cabinet earns its place when you want one lockable door, one gasket line and hidden stub-ups, or when the relay panel is indoor-rated and needs a Type 4X shell around it.
Does a ground rod at the pad replace the equipment grounding conductor?
No, and NEC 250.54 is clear about the order: the rod is an auxiliary electrode. Bond it to the equipment grounding conductor, size that conductor from the feeder overcurrent device using NEC Table 250.122, and let the EGC carry fault current; the earth is not part of the fault path under NEC 250.4(A)(5).
How tall can the pad-mounted cabinet be before breaker handles break the limit?
NEC 240.24(A) sets the ceiling at 2.0 m (6 ft 7 in, or 79 in) from grade to the center of the highest operating handle. The 60 in cabinet on the pad reaches 64 in (5 ft 4 in), leaving 15 in of margin. Pad thickness plus cabinet height under 79 in clears it.
NEMA 3R or NEMA 4X for a soccer field relay cabinet?
Type 3R covers rain, sleet and snow, so a pad that never sees sprinkler overspray or a wash hose can run a custom Type 3R build. Irrigation overspray, spring rinse-down and any corrosion exposure call for Type 4X; NEMA 250 gives the X an extra 200 hours of salt spray in the type test. On an irrigated turf field, order the 4X stainless box.
Do field-drilled conduit holes keep the NEMA 4X rating?
Only when every hole is sealed with a gland the maker documents for Type 4X service, installed as the gland instructions describe. Factory-cut entries arrive with the manufacturer's rating intact and land exactly on your drawing, which is why the bottom conduit cutouts belong on the order from day one.
What should I send with the quote request?
Inside dimensions of the relay panel, the material (304 or 316L), the NEMA type, and the bottom cutout positions and diameters for the stub-ups. Custom work is delivered in 10 business days counted from your approval of the drawing, anywhere in the world.
