When an industrial plant falls within the scope of the Grid Code, the first thing CRE asks for are the electrical studies. This is not bureaucratic paperwork: they are technical analyses signed by a certified expert that demonstrate your facility operates within the safe limits of the National Electric System. Without them, CRE can deny interconnection or expansion permits or, in severe cases, order disconnection.
This guide covers the 7 main studies: what they are for, when they are required, what documentation each delivers, and what investment ranges to expect.
Why so many studies?
Each study answers a different technical question about how your facility behaves relative to the SEN. CRE does not request them arbitrarily: each one reveals a different operational risk. A plant may have an impeccable short circuit and still have poorly coordinated protections. That is why they are complementary, not substitutes.
The 7 electrical studies of the Grid Code
1. Short-circuit study
Question it answers: how much current flows if there is a fault in your facility, and will the breakers withstand it?
When it is required: before the initial interconnection, every time the topology is modified (new transformer, new feeder), and at least every 5 years even if there are no changes.
What it delivers: three-phase, single-phase, and line-to-ground short-circuit currents at each node of the facility, compared against the nominal interrupting capacity of the equipment. It identifies equipment under overstress.
Typical range: $80,000 – $250,000 MXN depending on the size of the facility.
2. Protection coordination study
Question it answers: which protection operates first if there is a fault, and how is cascade tripping avoided?
When it is required: together with the short-circuit study (one depends on the other), and every time relay settings are modified or new protections are added.
What it delivers: coordinated time-current curves (TCC) for each protection zone, recommended relay settings, selectivity justification. It is one of the deliverables CRE reviews in the most detail. See protection coordination under the Grid Code.
Typical range: $120,000 – $400,000 MXN.
3. Load-flow study
Question it answers: how is power distributed across your facility under different operating scenarios?
When it is required: for the initial interconnection, before any significant load expansion, and to validate N-1 contingencies if your facility is critical.
What it delivers: voltages at each node, active and reactive power flows, loadability of transformers and conductors, identification of bottlenecks.
Typical range: $90,000 – $280,000 MXN.
4. Power-quality study
Question it answers: does your facility inject harmonics, flicker, imbalances, or sags outside the Grid Code limits?
When it is required: for the initial interconnection when the plant has significant non-linear loads (large drives, furnaces, welders), and every 2–3 years in continuous operation.
What it delivers: real measurements taken with a power-quality analyzer over 7–30 days, comparison against IEEE 519 and CRE limits, a proposal of corrective measures if there are deviations (passive filters, active filters, capacitor bank). Detail in industrial power quality: harmonics, flicker, sags.
Typical range: $150,000 – $450,000 MXN (includes rental or use of the analyzer).
5. Grounding and earthing systems study
Question it answers: do the resistance and configuration of the grounding system adequately protect people and equipment?
When it is required: for the initial interconnection and every 5 years, plus every time the grounding system is modified.
What it delivers: soil resistivity measurement, grounding system configuration (grids, rods, conductors), calculation of step and touch voltages, comparison against IEEE 80.
Typical range: $60,000 – $180,000 MXN.
6. Large motor starting study
Question it answers: does the starting of your main motors cause voltage dips dangerous to the facility or to the SEN?
When it is required: when the plant has induction motors larger than 250 HP or synchronous motors, or when an existing motor is replaced with one of greater capacity.
What it delivers: current and voltage profiles during starting, comparison against the Grid Code dip limits, recommendation of starter type (direct, soft, drive, autotransformer).
Typical range: $50,000 – $150,000 MXN per motor studied.
7. Transient stability study
Question it answers: does your own generation (if you have cogeneration or backup) stay synchronous with the SEN under faults or load losses?
When it is required: when the plant has its own generation interconnected to the SEN (cogeneration, large backup generators in parallel). It does not apply to all plants.
What it delivers: dynamic analysis of typical events (short circuit on a nearby line, sudden load loss, load shedding), evaluation of critical clearing time, recommendations for governor and exciter settings.
Typical range: $200,000 – $600,000 MXN. Applies only to specific cases.
When are they required together vs separately?
Studies 1, 2, and 3 (short circuit, coordination, load flow) are frequently requested as a package because one feeds the other. It is inefficient to run them separately: most certified firms quote these 3 as an initial bundle.
Studies 4 and 5 (power quality and grounding) are independent and can be run in any order.
Studies 6 and 7 are specific: only if your facility has the conditions that trigger them.
Who signs them
Each study must be signed by an electrical installations expert certified by CRE or by the Ministry of Energy. It is not enough for an external engineer to sign it: the signature must carry a registration in good standing before the authority. If your current firm does not have it, CRE rejects the deliverable and you lose time and money.
Typical execution times
| Study | Time from kick-off |
|---|---|
| Short circuit | 3–6 weeks |
| Coordination | 4–8 weeks |
| Load flow | 3–5 weeks |
| Power quality | 6–12 weeks (includes measurement campaign) |
| Grounding | 3–4 weeks |
| Motor starting | 2–4 weeks per motor |
| Stability | 8–14 weeks |
If you need them all, plan for 3–6 months of total schedule (running them in parallel where possible). These studies are Phase 2 of the 18-month Grid Code compliance plan, so it is worth fitting them into a broader schedule.
Integrated package costs
For a typical industrial plant of 2–5 MW requiring studies 1 through 5 (the most common), the total investment range falls between $400,000 and $1,200,000 MXN, including:
- Technical firm fees
- Rental or use of power-quality analyzers
- Field measurements (real short circuit, soil resistivity)
- Formal technical reports accepted by CRE
- Support during presentation to the authority
Common errors that delay approval
- Outdated studies: CRE rejects studies more than 5 years old if they were not updated after changes.
- Lack of certified-expert signature: even if the technical study is well done.
- Inconsistency between studies: for example, different transformer data between the short-circuit and load-flow studies.
- Not including planned future loads: if you are going to expand in 12 months, the study must account for it.
- Absence of real measurements in the power-quality study: "theoretical" studies without a measurement campaign are not accepted.
Do you need help with the studies?
At Enerlogix we coordinate the electrical studies as part of our Grid Code service, within the 360 Management Plan: we contract the certified experts, oversee technical quality, integrate the deliverables, and present them to CRE on your behalf. This prevents your internal team from having to manage 3–5 different firms in parallel.
If your plant needs to carry out electrical studies in the next 12 months — whether for general compliance, for migration to the MEM, or due to an open observation —, request a free 360 Management Plan evaluation. We tell you which studies apply to your case, how much they cost, and in what order it makes sense to execute them.
More context in the Grid Code 2026 pillar — Complete Guide and in CRE penalties for Grid Code non-compliance.
Frequently asked questions
There are 7 main studies: short circuit, protection coordination, load flow, power quality, grounding and earthing systems, large motor starting, and transient stability. They are complementary, not substitutes: each answers a different technical question and reveals a different operational risk relative to the National Electric System.
For a typical industrial plant of 2 to 5 MW requiring studies 1 through 5, the most common, the total investment range falls between 400,000 and 1,200,000 MXN. It includes firm fees, rental of power-quality analyzers, field measurements, formal reports accepted by CRE, and support during the presentation to the authority.
If all are needed, it is best to plan for 3 to 6 months of total schedule, running them in parallel where possible. Per study: short circuit from 3 to 6 weeks, coordination from 4 to 8, load flow from 3 to 5, power quality from 6 to 12 weeks including the measurement campaign, grounding from 3 to 4, and stability from 8 to 14 weeks.
Each study must be signed by an electrical installations expert certified by CRE or by the Ministry of Energy, with a registration in good standing before the authority. It is not enough for an external engineer to sign it: if the firm does not have a registration in good standing, CRE rejects the deliverable and time and money are lost.
Studies 1, 2, and 3, short circuit, coordination, and load flow, are usually requested as a package because one feeds the other, and they are quoted as an initial bundle. Studies 4 and 5, power quality and grounding, are independent and run in any order. Studies 6 and 7, motor starting and stability, only apply if the facility has the conditions that trigger them.
